LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

'Received        /?  L-fl/^^        ,  i 
t/lcct%sions  No.  y.nj.  JO  .  Class  No. 


THE    USES   OF   COMPRESSED    AIR 

WITH   ILLUSTRATIONS 


SECOND    EDITION 


ADDISON      C.      RAND 


NEW   YORK 
THE   REPUBLIC    PRESS 


1895 

D.  VAN  NOSTRAND  COMPANY, 
NEW  YORK. 


s 


Copyright,  1894. 

ADDISON  C.  RANU, 

New  York. 


THE    USES   OF   COMPRESSED    AIR 

WITH    ILLUSTRATIONS 


SECOND    EDITION 


ADDISON      C.      RAND 
u 


NEW    YORK 
THE   REPUBLIC    PRESS 

1895 


Copyright,  1894. 

ADDISON  C.  RAND, 

Nqw  York. 


fif*    0?  THH         ^\ 

FIVSBiSItYj 


CONTENTS 

INTRODUCTION,  -  PAGE  5 

CONSTRUCTION   OF   AN   AIR  COMPRESSOR,      -  ...  "    9 

TUNNELLING  AND   DRILLING. 

Tunnelling  to  Utilize  the  Power  of  Niagara,  12;  Drilling  in  Rock,  17;  Portable  Rotary  Drill,  2 1 ; 
Working  and  Drilling  in  Caissons,  23 ;  Drilling  and  Channelling  Canals,  (Chicago  Drainage  Canal), 
25;  Tapping  Iron  Furnaces,  31 ;  Use  in  Soft  Ground  Tunnels,  34. 

PUMPS  AND   PUMPING. 

The  Air  Lift  Pump,  for  Artesian  Wells,  37;  The  Relation  of  Air  to  the  Water  Supply  of  Towns,  39; 
The  Automatic  Pump,  42 ;  Pumping  Motor,  42. 

RAILWAY  APPLIANCES. 

The  Air  Brake,  43;  Air  Brake  upon  Street  Cars,  47;  Safety  Appliances,  49;  Railway  Gates,  56; 
Uses  in  Railway  Shops,  59;  Air  Locomotives,  66;  Unloading  Cars,  68;  Lifting  Rails,  69;  Street 
Railway  Motor,  70. 

OPERATING  SHOPS,  TOOLS  AND   ENGINES. 

Operating  Shops,  74;  Portable  Staybolt  Cutter  and  Riveter,  76;  Walking  and  Overhead  Travelling 
Cranes,  80;  Air  Tools,  83;  Operating  Clocks  and  Engines  in  Paris,  86;  Coal  Mining  Machines,  88. 


GUNS,  TORPEDOES  AND  TUBES. 

Air  Guns  on  the  Cruiser  "Vesuvius,"  91;  The  Torpedo  Gun,  93;  The  Torpedo  Gun  Cruiser 
"  Nictheroy/'  93;  Disappearing  Gun  Carriages,  96;  Operating  the  Torpedo  Gun  on  the 
"  Destroyer,"  98;  Locomotive  Torpedoes,  102;  Transportation  Tubes,  104. 

AERATION  AND  ATOMIZING. 

Aerating  Fuel,  105 ;  Aerating  Water,  108;  Refining  Asphalt  by  Aeration,  1 1 1 ;  Increasing  the  Brilliancy 
of  Lamps,  112;  Mixing  Nitroglycerine,  113;  Painting,  114. 

APPLICATION    OF  AIR   PRESSURE. 

Raising  Acids,  116;  Making  Silk  from  Wood  Pulp,  117;  Compressed  Air  System  of  Conveying 
Sewage,  118;  Raising  Beer,  119;  Compressing  Gases,  120;  Raising  Pressure  of  Natural  Gas, 
123;  Preserving  Timber  (Vulcanizing),  125;  Raising  Sunken  Vessels,  126;  Ice  Making  and 
Refrigerating,  127;  Compressed  Air  Tire,  129;  Transmission  of  Power,  153. 


INTRODUCTION. 

SHIS  little  volume  is  issued  to  present  a  comprehensive  account  of  the  important  uses 
which  have  been  found  for  compressed  air,  within  a  very  short  period,  and  the  utility 
of  air  as  a  motive  power.  It  is  not  intended  as  a  scientific  exposition.  The  author 
has  endeavored  to  describe  the  principal  uses  of  air  in  a  common  sense  way,  and  has 
explained,  though  less  at  length,  many  possible  uses.  A  great  number  of  carefully  prepared  illustra- 
tions are  presented.  Even  among  the  well  informed,  comparatively  few  persons  realize  the  diversified 
interests  using  compressed  air  in  some  form,  and  to  many,  doubtless,  the  contents  of  this  book  will 
be  a  revelation.  Air,  the  simplest  and  most  abundant  element,  has  become  a  powerful  factor 
in  the  arts,  sciences,  and  manufactures.  Its  employment  as  an  agent  in  the  transfer  of  power  is 
attended  with  absolute  safety  and  certainty. 

The  most  important  application  of  compressed  air  in  the  past  has  been  that  to  rock 
drills  in  tunnels  and  mines,  and  in  both  these  fields  of  activity  the  drill  has  accomplished  wonders 
within  a  decade.  America  can  claim,  at  Hoosac  Tunnel,  the  first  general  application  of  the  rock 
drill,  followed  by  the  work  at  Hell  Gate,  and  in  all  the  tunnels  of  the  Alps,  and  in  our  own  and  other 
countries.  The  New  York  Aqueduct,  30  miles  in  length,  was  made  with  such  remarkable  speed 
only  by  the  use  of  compressed  air  driving  the  rock  borers.  Another  instance  of  rapid  tunnelling 
by  the  use  of  compressed  air  is  cited  in  the  work  at  Niagara  Falls,  where  7,250  feet  of  tunnel  was 
excavated  in  the  short  space  of  six  months,  and  it  is  to  be  observed  that,  in  locations  permitting  the 
use  of  shafts  at  frequent  intervals,  a  tunnel  ten  miles  in  length  can  be  constructed  as  quickly  as 
that  of  one  mile. 


This  fact  has  a  bearing  upon  the  question  of  providing  quick  transit  in  cities  built  upon 
a  rock  foundation,  inasmuch  as  modern  engineering  permits  the  construction  of  tunnels  in  rock  with 
celerity,  and  comparatively  small  cost,  and  without  large  land  damages.  It  is  claimed  by  experts  in 
the  construction  of  tunnels  that  a  deep  tunnel  system  (which  may  contain  a  four-track  railroad,  to 
be  laid  in  two  decks,  of  two  tracks  each),  can  be  built  and  lined  with  white  glazed  brick  and 
provided  with  suitable  shafts,  within  the  limit  of  cost  of  two  million  dollars  per  mile,  excluding 
the  cost  of  surface  stations. 

The  question  of  raising  and  lowering  passengers  has  been  practically  solved  at  the 
Eldorado  Station  of  the  North  Hudson  County  Railroad,  near  Wehawken,  where  one  elevator  has 
carried  1 60  passengers,  making  the  up  trip  of  153  feet  in  40  seconds,  and  the  down  trip  in  35 
seconds.  Objections  to  an  underground  system,  based  upon  the  limited  facility  for  transferring 
passengers  to  and  from  the  railroad,  is  fully  met  by  this  illustration. 

Against  such  a  system  the  chief  objections  so  far  raised  are  the  smoke  and  discomfort  of 
the  London  underground  tunnel,  which  has  been  cited  as  an  obnoxious  example.  In  view,  however, 
of  the  recent  improvements  in  electric  and  compressed  air  motors,  it  is  obvious  that  this  objection 
is  no  longer  valid. 

The  marked  influence  of  the  rock  drill  operated  by  compressed  air,  upon  the  mining 
industry,  and  especially  upon  that  of  precious  metals,  is  a  matter  that  so  far  has  received  little 
attention.  A  study  of  the  increase  of  silver  production  shows  to  a  marked  degree  that  it  is 
coincident  with  the  introduction  of  compressed  air  drills.  The  decreased  cost  of  excavation  is  not, 
however,  the  only  advantage  obtained  from  the  use  of  drills,  for  the  increased  speed  with  which  a 
mine  is  opened  up  and  made  a  factor  in  producing  metal,  is  of  almost  equal  importance. 


With  few  exceptions,  the  modern  method  of  mining  cannot  be  as  readily  applied  to 
obtaining  gold  as  it  can  be  to  the  less  valuable  ores,  and  it  is  significant  that  the  increase  in  the 
production  of  gold  has  been  very  slight  during  the  last  twenty  years.  Within  three  years,  however, 
the  rock  drill  has  been  largely  introduced  in  the  gold  mines  of  Johannesburg,  South  Africa — to  the 
extent  of  about  three  hundred  machines — and  the  mines  are  now  producing  at  the  rate  of  about 
$2,000,000  per  month. 

The  uses  of  compressed  air  with  which  the  public  is  most  familiar  is  undoubtedly  that 
of  the  air  brake  upon  railroad  cars,  and  of  the  pneumatic  tire  of  the  bicycle,  both  of  comparatively 
recent  adaptation. 

Compressed  air  bids  fair  to  find  also  a  very  wide  application  to  pumping  from  artesian 
wells.  It  is  much  applied  in  atomizing  crude  petroleum  for  use  under  boilers,  forges,  etc. ;  other 
important  uses  of  air  are,  seasoning  wood,  driving  locomotives  in  mines,  coal  mining  machines, 
underground  haulage,  hoisting,  and  street  cars.  There  are  also  a  multitude  of  other  important  uses, 
both  of  peace  and  war. 

No  attempt  has  been  made  in  this  book  to  discuss  at  length  the  principles  of 
air  compressing  or  the  construction  of  compressors,  but  it  should  be  clearly  understood  at  the 
outset,  that  modern  ingenuity  in  compressing  air  makes  operations  practical  which  formerly  were 
forbidden.  To  the  pages  which  follow,  telling  their  own  stories  of  scope  and  utility,  the  reader  is 
referred,  who  desires  to  obtain  even  an  imperfect  idea  of  the  application  and  usefulness  of  compressed  air. 
It  is  more  than  likely,  however,  that  there  are  many  uses  of  compressed  air  not  described  in  these 
pages,  and  the  writer  solicits  from  his  readers  detailed  information  regarding  practical  uses  not  herein 
described.  It  is  not  unlikely  that  the  possible  usgs^^ampressed  air  may  be  added  to  another  issue. 


While  most  of  the  illustrations  are  from  photographs  made  by  the  direction  and 
at  the  expense  of  the  writer,  he  is  grateful  to  the  editors  of  the  technical  press  of  this  country  (to 
which,  with  few  exceptions,  his  investigations  have  been  limited)  for  many  facts,  illustrations  and 
courtesies.  Among  them  he  takes  pleasure  in  mentioning  THE  RAILROAD  GAZETTE,  THE  ENGINEERING 
RECORD,  MINING  AND  ENGINEERING  JOURNAL,  ENGINEERING  NEWS,  SCIENTIFIC  AMERICAN,  CASSIER'S 
MAGAZINE,  RAILWAY  MASTER  MECHANIC,  THE  RAILWAY  AGE  AND  NORTHWESTERN  RAILROADER,  THE 
HUB.  He  is  also  indebted  to  many  companies  and  individuals. 

ADDISON  C.  RAND. 
NEW  YORK,  March  i,  1894 


THE  CONSTRUCTION  OF  AN  AIR  COMPRESSOR. 

HE  air  compressors  now  in  general  use  in  the  United  States,  and,  indeed,  all  over  the 
world,  are  fitted  for  surface  cooling,  and  deliver  dry  air.     This  method  is  the  result  of 
long  experiment  and  experience,  and  practically  eliminates  the  physical  difficulty  of 
extremely  high  temperature  of  air  attendant  upon   compression,  which  up  to  recent 
years  made  the  practical,  economical  application  of  compressed  air  almost  impossible. 

Bearing  in  mind  that  special  compressors  are  constructed  for  special  requirements  or 
localities,  the  modern  air  compressor  is  generally  of  the  horizontal  duplex  type  of  steam  engine, 
with  air  cylinders  behind  and  in  line  with  the  steam  cylinders,  the  piston  rods  of  the  latter  being 
extended  to  couple  to  those  of  the  air  cylinders. 

The  operation  of  air  compression  is  directly  the  reverse  of  the  steam  engine  ;  in  the 
former  the  initial  resistance  is  nothing,  increasing  to  slightly  above  reservoir  pressure  at  end  ot 
stroke  ;  in  the  latter  the  pressure  of  the  boiler  is  only  found  at  the  beginning  of  the  stroke,  and  then 
rapidly  decreases  by  expansion.  To  equalize  the  variable  power  of  steam  to  the  variable  resistance 
of  the  air,  a  heavy  fly  wheel  is  used,  in  which  the  power  of  the  steam  engine  is  stored  at  the 
beginning,  to  be  expended  on  the  air  pistons  at  the  end  of  the  stroke. 

While  slide  valve  engines  (provided  with  adjustable  cut-off  valves)  of  a  substantial  type, 
give  economical  and  satisfactory  results  for  good,  simple  working  air  compressors,  the  highest 
practical  known  economy  is  accomplished  by  a  design  using  a  cross  compound  condensing  Corliss 
steam  engine,  driving  compound  air  compressing  cylinders,  having  an  inter-cooler  between  them. 
The  atmospheric  air  is  brought  from  outside  the  engine  house,  through  conduits  to  the  first  air 


cylinder,  where  it  is  drawn  in  by  the  suction  of  the  piston,  through  poppet  inlet  valves  located  in 
the  cylinder  heads  ;  the  returning  stroke  of  the  piston  compresses  it  to  a  sufficient  pressure  to  open 
the  discharge  poppet  valves  and  cause  it  to  be  passed  into  a  surface  cooler,  where  the  heat  is 
extracted  before  entering  the  second  cylinder.  In  this  cylinder  the  final  stage  of  compression  is 
accomplished,  the  air  then  being  delivered  to  storage  tanks  to  be  drawn  off  as  desired. 

The  poppet  inlet  and  discharge  valves  are  constructed  so  as  to  be  moved  either  by  the 
air  pressures,  or  by  positive  mechanical  attachments,  to  suit  requirements. 

When  air  at  very  high  pressure  is  needed,  the  compression  is  done  in  three  or  four 
stages,  by  air  cylinders  in  suitable  number  and  proportions.  Cooling  water  is  circulated  around  the 
air  cylinders  and  heads,  and  in  cases  through  pistons  and  rods. 

Compressors  are  also  driven  by  water,  electrical  or  other  power,  through  direct 
connection  or  the  medium  of  belts  or  gearing.  The  easy  transmission  of  air  through  pipes  for  long 
distances,  places  no  practical  restriction  upon  their  location,  and  they  are  frequently  built  of  odd 
design  to  be  placed  in  limited  space  on  shipboard,  etc.,  and  for  handling  different  gases. 

Air  compressors  are  built  of  all  sizes  and  capacities,  from  a  size  sufficient  for  operating 
one  drill,  to  the  Mammoth,  that  will  drive  70  at  the  same  time. 


TUNNELLING  TO  UTILIZE  THE  POWER  OF  NIAGARA. 

)NSERVATIVE  engineers  agree  in  declaring  that  much  more  than  all  the  horse- 
power now  actually  in  use  on  this  Continent,  is  contained  within  the  narrow 
limits  of  the  Niagara  River.  The  census  of  1890  made  no  attempt  to  compute  the 
total  combined  steam  and  water  power  used  in  the  United  States,  as  was  done  in 
1880,  but  it  must  have  amounted  to  4,000,000  horse  power.  The  Niagara  River 
represents  5,878,100  horse  power,  thus  vastly  greater  than  all  the  power  in  use  in  this  country. 

It  has  long  been  the  dream  of  engineers  and  capitalists  to  utilize  some  of  this  marvelous 
supply  of  power,  and  though  a  few  thousand  horse  power  have  been  employed  for  some  years 
by  means  of  a  crude  canal,  the  tunnel  and  canals  constructed  by  the  Niagara  Falls  Power  Company 
form  the  first  elaborate  attempt  to  chain  a  portion  of  Niagara's  wonderful  strength.  This  gigantic 
undertaking  was  made  practicable  by  the  use  of  rock  drills  operated  by  compressed  air.  With 
these  drills  a  tunnel,  7,250  feet  in  length  was  constructed  to  form  a  tail  race,  starting  from  just 
above  the  water-level  below  the  Falls,  and  running  under  the  village  of  Niagara  at  a  depth  of  200 
feet ;  the  upper  end  of  the  tunnel  being  adjacent  to  the  river  bank  and  beneath  a  large  tract  of  land 
owned  by  the  Company.  The  grade  of  the  tunnel  is  36  feet  to  the  mile  ;  it  is  19  feet  wide  and  21 
feet  high  inside  the  brick  work,  which  is  of  most  substantial  character.  The  sinking  of  the  shafts 
was  attended  with  many  difficulties,  on  account  of  the  large  amount  of  water  entering  them, 
but  when  they  were  completed,  the  entire  tunnel  was  excavated  in  the  amazingly  short  period 
of  six  months,  by  the  contractors,  Messrs.  Rogers  &  Clements.  The  boring  was  conducted 
in  three  benches,  the  upper  one,  or  heading,  (see  cut),  being  driven  first,  and  in  advance.  The 


next  bench  was  slightly  behind,  and  the  lowest,  behind  that,  the  general  appearance  of  the  three 
benches  being  that  of  three  steps.  The  excavated  matter,  from  the  two  upper  benches  was  with- 
drawn over  platforms,  thus  permitting  simultaneous  work  at  three  levels  without  interference.  The 
cost  of  the  excavation  alone  was  $400,000,  and  when  walled  and  completed  with  arching  of  brick, 

$1,300,000.     In  driving  this  tunnel,  three  shafts  were  sunk,  in  order  to  expedite  the  work the 

Zero  shaft  at  the  portal,  extending  93  feet  from  the  top  of  a  ledge  to  the  tunnel  soffit  ;  No.  2 
2,650  feet  from  the  portal,  sunk  260  feet,  and  No.  3,  5,200  feet  from  the  portal  is  196  feet  in  depth. 
The  general  plan  of  the  main  supply  canal  includes  an  upper  reach  extending  500  feet 
inwardly  from  the  river,  thence  parallel  to  the  river  in  a  down-stream  direction  for  5,000  feet,  where 
a  lower  reach  200  feet  wide  and  1,200  feet  long  connects  this  end  with  the  river.  These  sections, 
adapted  to  different  power  requirements,  will  be  connected  by  gates  when  completed.  Along  these 
reaches  central  power  stations  will  be  erected,  obtaining  their  power  from  turbine  wheels.  The  total 
horse-power  which  this  system  is  expected  to  develop  is  125,000.  The  power  produced  by  the 
tunnel  capacity  is  equal  to  the  water-power  of  Lawrence,  Lowell,  Holyoke,  Turner's  Falls, 
Manchester,  Bellow's  Falls,  Lewiston,  Cohoes,  Oswego,  Paterson,  Augusta,  Ga.,  Minneapolis, 
Rochester,  and  Lockport,  combined.  But  the  Company  is  moving  cautiously  and  begins  by 
generating  5,000  horse-power  by  compressed  air,  and  5,000  by  electricity,  adding  in  units  of  2,500 
or  5,000,  to  whichever  power  proves  the  more  profitable.  It  is  estimated  that  this  Company  can 
supply  the  city  of  Buffalo  with  all  the  power  it  requires  at  a  rate  much  below  ordinary  cost  pf 
steam,  and  that  Rochester,  Syracuse,  and  other  cities  throughout  Central  New  York  can  be  profit- 
ably supplied.  It  is  even  claimed  that  eventually  the  belts  in  New  York  City  itself,  440  miles 
away,  will  be  turned  by  the  power  of  Niagara. 

'4 


"5 


DRILLING  IN  ROCK. 

'N  connection  with  rock  work,  all  modern  engineering  is  dependent  upon  the 
rock  drill,  which,  in  addition  to  general  use  in  America,  is  found  at  work  in  the 
mines  of  Europe,  Australia,  South  Africa,  South  America,  Mexico,  Japan,  and  in 
fact  keeping  pace  with  the  advance  of  civilization.  Perhaps  a  better  statement 
is  that  in  recent  years  the  rock  drill  indicates  the  advance  of  civilization.  It  is 
estimated  that  one  medium  sized  rock  drill  will  do  the  work  of  12  men,  and 
will  drill,  depending  upon  the  hardness  of  the  rock,  from  20  to  1 50  lineal  feet  of 
hole  per  working  day.  The  motive  power  employed  is  compressed  air  or  steam,  though 
electricity  has  been  tried.  Except  for  outside  work,  where  steam  can  be  used,  experience  demon- 
strates that  air  is  far  more  economical  and  satisfactory.  The  air  used  to  drive  the  drills  is  worth  in 
ventilation  alone,  nearly  the  cost  of  the  fuel  required  to  operate  the  compressor.  The  air 
compressor  may  be  situated  in  any  location  convenient  for  steam  or  water  power,  and  air,  though 
led  in  piping  for  one  or  more  miles  through  the  mine  or  tunnel,  retains  most  of  the  pressure  indicated 
at  the  compressor.  The  successful  operation  of  the  principal  iron  and  copper  mines  is  largely  duetothe 
use  of  rock  drills.  The  rock  drill  has  developed  the  mines  of  South  Africa  in  four  years  to  a  production 
of  $24,000,000  annually,  these  mines  being  exceptionally  well  adapted  to  the  use  of  power  drills. 
And  such  modern  engineering  feats  as  the  Hoosac,  Mount  St.  Gothard  and  all  railroad  tunnels ; 
Hell  Gate,  the  Niagara  Tunnel,  the  tunnels  under  Bergen  Hill,  the  Palisades,  and  the  Croton  Aqueduct, 
were  carried  to  success  by  rock  drills.  These  machines,  with  the  air  compressing  plant  to  operate 
them,  are  now  as  indispensable  in  tunneling,  mining  and  excavating,  as  the  air  brake  on  railroad  trains. 

'7 


THE  ROCK  DRILL 

ON  TRIPOD. 


The  effect  of  the  introduction  of  rock 
drills  for  mining  purposes  is  shown  in  Roth- 
well's  report  on  The  Mining  Industry  for  1892, 
p.  137.  Taking  the  Atlantic  Mine  as  an  ex- 
ample, the  cost  sheets  of  different  years  show 
the  cost  in  1 88 1 ,  the  year  before  the  introduc- 
tion of  drills,  to  have  been — for  stoping,  per 
fathom,  14.35,  against  4.33  for  1891  ;  for 
drifting,  i  o.  08,  against  4. 92  for  1 89 1 .  Though 
it  is  fair  to  state  that  a  portion  of  this  reduc- 
tion in  cost  is  due  to  the  use  of  high  explo- 
sives. 

Rock  drills  are  of  varying  sizes,  due  to  the 
diameter  and  depth  of  holes  to  be  drilled, 
mounted  on  tripods,  columns,  or  shaft  bars,  as 
desired.  The  drilling  steel,  a  separate  and 
changeable  piece,  is  an  extension  of  the  piston 
rod,  and  strikes  from  400  to  800  blows 
on  the  rock  per  minute,  depending  upon 
the  size  of  the  machine.  The  mechan- 
ism is  simple  but  strong  and  durable, 
consisting  of  a  cylinder  containing  a  long  pis- 


SECTION  OF  A  MINE,  SHOWING  SHAFTS,   DRIFTS,  WINZES,   SHAFT  HOUSES,  ETC. 


ton,  the  extension  of  which  carries  a  chuck  that  holds 
the  drill  steel.  The  valve  admitting  air  to  each  end 
of  the  cylinder  is  operated  either  by  mechanical  or 
pressure  connection  with  the  main  piston.  A  suitable 
device  causes  the  pis'ton,  and  thus  the  drill  steel,  to 
rotate  while  drilling,  a  necessary  feature  in  drilling 
rock.  A  long  practical  experience  has  been  necessary 
to  bring  the  design  of  the  rock  drill  to  its  present  per- 
fected state,  as  the  nature  of  its  work  is  most  severe. 
Several  styles  of  compressed  air  drills  compete  for 
public  favor,  but  they  do  not  vary  essentially  in 
principle  from  the  above  description,  which  may  be 
taken  as  representative. 

PORTABLE  COMPRESSED  AIR  ROTARY  DRILL  FOR 
METAL  WORKING. — Compressed  air  is  now  used  to  operate  a  port- 
able boring  tool  for  drilling  holes  in  metal  and  for  reaming  holes  that 
already  have  been  punched.  For  reaming,  the  drill  is  handled  and 
operated  by  one  man,  no  brace  being  required,  which  is  not  the  case 
when  the  drill  is  used  for  drilling  holes  in  solid  plates.  The  drill  is  then 
fed  to  its  work  by  a  hand  wheel  between  the  cylinder  and  arm  of  a 
brace.  Moderate  air  pressure  operates  this  drill,  (of  which  a  picture  is 
given,)  and  air  may  be  conveyed  in  one-inch  rubber  hose. 


DRILLING  AND  WORKING  IN  CAISSONS.— In  a  closed  chamber  like  a 
caisson,  the  replacing  of  foul  by  pure  air  is  almost  impossible  by  natural  means,  and  as  the 
condition  of  the  men  depends  directly  upon  the  purity  of  the  air  they  breathe,  it  is  of  vital 
importance  to  preserve  it  in  its  normal  state  and  prevent  pollution.  The  bridge  which  spans  the 
Harlem  River  at  One  Hundred  and  Eighty-First  Street,  New  York,  presented  interesting  engineering 
problems  during  the  course  of  its  construction,  of  which  the  most  perplexing  was  the  sinking 
of  the  caisson  along  an  incline  of  rock.  Borings  showed  that  fifteen  feet  from  the  surface  of 
the  water  the  eastern  edge  of  the  foundation  would  encounter  rock,  sloping  downward  at  a 
sharp  angle  toward  the  center  of  the  river,  while  on  the  rock  lay  the  soft  mud  of  the  river  bed. 
Thus,  during  the  greater  part  of  its  downward  course,  the  caisson  rested  upon  rock,  mud  and 
sand.  To  sink  it  vertically,  therefore,  was  extremely  difficult,  as  there  was  a  constant  tendency 
to  shift  sidewise  toward  the  channel.  Within  this  caisson  it  was  found  necessary  to  work  and  drill 
for  blasting,  by  compressed  air. 

The  bottom  of  the  caisson  was  54  feet  wide  by  104  feet  long,  the  top  being  one  foot 
less.  The  roof  was  six  feet  thick,  and  constructed  of  pine  timbers  one  foot  square,  the  layers 
running  differently.  The  walls,  which  were  three  feet  thick,  were  made  also  of  pine.  The  inner 
portion  of  each  wall  was  bevelled  off  to  form  a  shoe,  or  cutting  edge,  which  was  nine  inches  wide, 
protected  by  an  oak  strip.  The  outside  walls  were  covered  with  a  three  inch  sheathing,  and  the 
interior  was  sheathed  also.  From  the  botton  of  the  shoe  to  the  top  of  the  caisson  measured  13  feet, 
the  interior  being  seven  feet  in  height.  Longitudinal  partitions  cut  the  chamber  into  three  compart- 
ments, two  feet  thick  by  five  feet  high,  with  suitable  openings.  The  supply  lock,  through  which 
passed  the  excavated  material  and  all  supplies,  was  in  the  center  of  the  roof.  The  shaft  of  this  lock 

23 


was  five  feet  in  diameter  and  extended  above  the  surface  of  the  water.  To  the  bottom  of  the  shaft, 
which  just  entered  the  chamber  of  the  caisson,  was  attached  a  rectangular  air  lock,  provided  with 
doors  at  two  opposite  sides,  which  permitted  loading  and  unloading  at  once.  At  the  botton  of  the 
shaft  was  a  third  door,  and  when  the  two  inner  doors  were  closed  the  pressure  of  the  air  admitted 
to  the  lock  was  made  to  equal  that  in  the  caisson,  and  the  shaft  door  was  then  opened  ;  after  which 
excavated  material  was  hoisted  to  the  top.  The  lock  for  the  workmen  was  in  the  top  of  the  shaft, 
extending  through  the  roof.  It  was  1 2  feet  by  4  feet,  provided  with  a  closed  chamber  at  each  end. 

The  same  air  compressor  which  supplied  the  pure  air  to  the  workmen  within  the  caisson 
furnished  also  the  power  to  operate  the  drills,  about  75  pounds  pressure  being  required  for  the  drills 
and  1 8  pounds  in  the  caisson.  After  each  blast  the  loose  material  was  extracted  from  about  the 
shoe,  permitting  it  to  settle,  and  as  the  caisson  descended  the  masonry  of  the  pier  was  added  on 
top. 

DRILLING  IN  CANALS— THE  CHICAGO  DRAINAGE  CANAL.— The  use  of  com. 
pressed  air  to  operate  rock  drills,  hoisting  engines  and  pumps  is  well  nigh  universal  in  the  mines 
of  the  United  States,  and  is  elsewhere  described.  Its  application  for  operating  the  same 
machines  when  used  on  the  surface  of  the  earth  in  rock  excavations,  is  not  as  common  as  the 
economy  effected  by  the  concentration  of  boiler  power  well  warrants. 

There  is,  however,  a  work  now  under  construction  in  the  United  States — a  notable 
public  work — in  which  most  of  the  small  engines,  above  referred  to,  to  the  number  of  over  one 
hundred,  are  satisfactorily  operated  by  compressed  air.  Before  the  erection  of  the  compressor 
plant  the  contractors  were  in  much  doubt  a<:  to  the  economy  of  the  project,  but  their  experience 
has  proved  to  be  in  favor  of  the  concentration  of  power  in  this  manner.  The  work  referred 

25 


CHICAGO  DRAINAGE  CANAL. 

From  photographs  of  the  preliminary  work.) 


to,  is  known  as  the  Drainage  Canal  of  Chicago,  Illinois,  and  while  the  work  is  one  of  so  great 
magnitude  that  were  it  located  in  other  countries  it  would  have  attracted  great  attention, 
yet  it  has  been  quietly  started  during  the  past  year  and  the  progress  on  a  goodly  portion  of  it  has 
been  very  marked,  being  up  to  the  time  contracts,  in  the  most  difficult  portions.  The  work  is  of  so 
important  a  character  that  while  the  large  engines  are  run  by  steam  direct,  yet  compressed  air  is  used 
to  so  great  an  extent  as  to  justify  a  general  but  brief  description  of  the  work  in  this  book.  It  has  been 
the  aim  of  the  writer  to  give  no  more  than  a  popular  description  of  the  different  uses  of  compressed 
air,  in  so  small  a  volume,  and  he  will  not  depart  from  this  practice  in  describing  the  Drainage 
Canal,  pointing  out  briefly  the  general  purpose  and  general  features  of  its  construction  as  seen  by  him 
in  his  visits,  and  as  explained  by  Mr.  L.  E.  Cooley,  Civil  Engineer,  its  most  persistent  projector. 

The  canal  is  primarily  designed  for  drainage  of  the  City  of  Chicago  and  vicinity  through  the 
Illinois  and  Mississippi  Rivers,  and  ultimately  to  connect  the  Lakes  with  the  Gulf  of  Mexico  for  the  navi- 
gation of  vessels,  and  in  this  its  projectors  are  far  seeing  in  their  plans  for  the  advancement  of  Chicago. 
The  work  is  carried  on  under  a  law  of  the  State  of  Illinois,  which  provides  for  a  commission  to  take 
lands,  raise  money  and  make  contracts.  The  cost  of  construction  is  borne  by  the  City  of  Chicago. 
Cities  less  enterprising  might  well  hesitate  before  assuming  such  a  responsibility,  but  the  former's 
enterprise  will  carry  it  through  speedily  and  cheaply.  The  progress  already  made  (October, 
1893,)  fully  justifies  the  making  of  this  prophecy,  and  the  writer  further  prophesies  that  in  its  speedy 
construction  it  will  be  the  forerunner  of  other  important  water-ways  in  the  United  States.  In  fact, 
it  seems  to  him  to  be  the  "  object  lesson  "  or  preparatory  school  for  the  construction  of  the  canal  at 
Nicaragua.  The  canal  is  now  being  built  between  Chicago  and  Joliet,  a  distance  of  about  thirty- 
two  miles,  twelve  miles  of  which  is  through  rock,  ten  through  clay,  ten  through  a  mixture  of  clay 

27 


and  "  indurated  earth  "  and  rock.  In  order  to  make  this  work  practical  it  has  been  found  necessary 
to  excavate  six  miles  of  rock,  two  hundred  feet  wide,  six  feet  deep,  in  which  the  Desplaines  River  is  to 
be  turned.  This  portion  is  about  completed.  The  amount  of  rock  excavation  is  about  1 4, 000,000  yards, 
and  earth  about  36,000,000.  The  prices  are  moderate,  but  remunerative  to  the  enterprising  con- 
tractors, who  have  adopted  modern  methods  and  machinery.  The  canal,  through  the  rock  sections,  is 
to  be  about  one  hundred  and  sixty  feet  wide  and  about  thirty-two  feet  deep.  The  excavation  is  made 
in  three  benches,  eleven  feet  each.  Channels,  ten  feet  deep,  are  first  made  by  percussion  channelling 
machines  on  each  side  of  the  canal,  then  the  eleven-feet  holes  that  have  been  bored  about  ten  feet  apart, 
are  blasted  and  the  rock  lifted  in  kibbles  and  dumped  at  one  side  of  the  canal.  When  sufficient  space 
has  been  cleared  on  the  first  bench,  the  second  is  channelled,  drilled  and  blasted,  and  after  that  the 
third  level  is  treated  in  the  same  manner.  At  one  point,  seen  by  the  writer  and  illustrated  herein, 
the  three  benches  are  close  to  each  other.  The  means  for  channelling,  drilling  and  blasting  have 
been  so  improved  in  recent  years,  that  this  work  proceeded  in  advance  of  the  hoisting  from  the  pit, 
and  it  remained  for  some  one  to  devise  and  adapt  a  speedier  and  cheaper  method  of  handling  the 
rock  than  by  carts  or  cars  commonly  used  (although  the  latter  is  a  speedy  method  for  the  first  level.) 
This  requirement  is  met  in  the  cantilever  hoisting  apparatus  shown  in  the  accompanying  illustrations, 
which  was  designed  by  the  same  parties  that  have  so  successfully  applied  a  somewhat  similar 
principle  to  the  machinery  for  the  transfer  of  iron  ore  from  the  lake  boats  and  barges  to  the  railroad 
cars  at  Cleveland,  Ohio,  and  other  places.  This  device,  as  adopted  for  the  canal  work,  allows  the 
use  of  large  buckets,  or  kibbles,  having  one  open  side,  to  be  so  placed  in  relation  to  the  broken  rock 
as  to  avoid  the  necessity  of  high  lifting  of  the  rock  in  loading.  This  fact  increases  the  work  of 
each  man  in  the  pit  about  30  to  40  per  cent.,  as  compared  with  the  high  lift  to  the  ordinary  con- 

29 


tractor's  car,  so  that  a  few  men  make  a  large  output  of  rock.  The  device  also  allows  of  a  high 
dump,  which  is  a  marked  advantage.  At  this  writing,  three  cantilevers  at  one  section  are  raising 
and  dumping  about  i  ,200  yards  of  rock  in  ten  hours.  The  capacity  for  hoisting  and  dumping  of 
the  cantilever  is  said  to  be  much  greater  than  that,  but  it  is  limited  by  the  power  of  the  laborers  to 
fill  the  buckets.  The  manufacturers  of  the  cantilever  express  the  opinion  that  the  practical  working 
capacity  will  yet  be  increased  40  to  50  per  cent. 

Perhaps  it  may  be  necessary  to  give  a  description  of  the  cantilever,  although  the  cut 
would  seem  to  indicate  its  operation.  Briefly,  four  tracks  are  laid  laterally  along  one  side  of  the 
canal.  On  these  tracks  are  the  four  trucks  on  which  rests  the  support  of  the  cantilever.  The 
motive  power  for  moving  the  cantilever  along  the  track,  is  inside  the  cantilever  supports.  The 
kibbles,  when  filled,  are  hoisted  rapidly,  traversed  to  the  rear  of  the  cantilever,  and  dumped.  The 
kibble  is  speedily  returned  to  the  pit  and  another  one  raised.  The  lateral  travel  of  the  whole 
structure,  and  transverse  and  hoisting  motion  of  the  kibbles,  controlled  by  one  operator,  enables  him 
to  lower  the  empty  kibbles  to  the  exact  point  desired. 

The  preliminary  work  of  excavation  was  done  by  horses  attached  to  carts,  and  by  cars 
operated  by  the  rope  haulage  system,  the  engines  having  been  stationed  on  the  bank  and  operated 
by  compressed  air.  Page  26  illustrates  the  method  adopted  and  also  the  channelling  machine 
making  a  second  cut  of  1 1  feet.  This  novel  method  of  making  a  rock  cut  canal  by  channelling  the 
sides  originated  in  the  United  States,  and  is  a  very  important  improvement,  saving  as  it  does  the 
necessity  of  masonry  sides  where  the  rock  is  not  much  broken. 

TAPPING  IRON  FURNACES  BY  COMPRESSED  AIR  DRILLS.— With  the  increase 
of  furnace  capacity  and  the  enlarged  "hearths"  in  modern  furnace  plants,  the  labor  and  danger 


attendant  upon  opening  and  closing  the  tapping  hole  (the  orifice  from  which  the  molten  metal  flows 
out),  have  considerably  increased.  In  old-fashioned  furnaces  of  small  capacity  these  operations  were 
speedy  and  unimportant.  Any  material,  such  as  brick  or  clay,  and  three  or  four  minutes  of  time, 
sufficed,  but  at  present,  fire  clay  and  graphite  are  used,  and  instead  of  one  ball,  from  three  to  five 
wheelbarrow  loads  are  required. 

To  open  the  furnace  at  casting  time,  one  of  these  deeply  stopped  iron  notches  requires 
the  labor  of  eight  or  ten  men,  drilling  with  a  heavy  bar  for  half  an  hour,  or  longer.  The  recent 
introduction  of  rock  drills  operated  by  steam  or  compressed  air  has  resulted  in  a  thoroughly  success- 
ful method  of  tapping  furnaces.  Between  two  columns  near  the  furnace,  a  horizontal  cross  bar  is 
swung,  so  fitted  that  it  can  be  raised  or  lowered  ;  to  this  bar  is  attached  a  frame  consisting  of  two 
parallel  irons  (the  other  end  of  the  frame  being  suspended  by  a  chain)  and  upon  this  frame  as  a  bed 
the  drill  travels,  the  latter  being  equipped  with  a  tubular  rod  which  takes  the  place  of  an  ordinary 
hand  screw,  and  forms  the  piston  rod  of  a  cylinder  for  feeding  the  drill  forward  or  backward,  as 
well  as  the  pipe  for  admitting  the  air  to  the  operating  cylinder.  When  it  is  time  to  cast,  the  frame 
is  lowered  to  the  proper  position,  and  the  drill  is  then  advanced  and  set  to  work.  As  soon  as 
molten  jron  is  reached,  the  bit  of  the  drill  is  rapidly  withdrawn  from  the  taphole,  and  the  latter 
now  being  open,  the  drill  is  swung  up  or  aside.  This  method  is  not  only  a  labor  saving  device, 
but  it  has  been  found  that  as  the  drill  cuts  a  true  circle,  the  hot  iron  and  cinders  are  not  so 
destructive. 


USE  OF  COMPRESSED  AIR  IN  SOFT  GROUND  TUNNELS. 

HE  importance  of  compressed  air  in  caissons  has  already  been  described.  Its  use,  how- 
ever, is  equally  necessary  in  working  through  the  decomposed  rock  and  mud 
(known  as  soft  ground  tunnelling)  sometimes  encountered  in  sub-aqueous  tunnels. 
The  construction  of  the  tunnel  under  the  East  River  and  Blackwell's  Island,  extending 

from  East  yist  Street,  New  York,  to 
Ravenswood,  L.  I.,  presented  serious 
engineering  difficulties  which  have 
been  overcome  partly  by  ingenuity 
and  partly  by  the  use  of  air  at  a  high 
pressure.  The  tunnel  is  being  built 
in  anticipation  of  a  law  excluding  gas 
manufactories  from  New  York  City, 
and  is  designed  to  convey  gas  from 
the  Ravenswood  works  to  New  York. 
It  is  ten  feet  in  diameter,  and  when 
completed  will  be  2, 500 feet  in  length. 
The  work  was  begun  about  a  year 
and  a  half  ago  by  sinking  a  shaft  at 
each  end — that  at  the  New  York  end 
being  141  feet  in  depth,  that  at 


34 


Ravenswood,  134  feet.  The  tunnelling  began  at  a  depth  of  124  feet  below  the  surface  of  the  river, 
and  60  feet  below  the  bed.  The  tunnel  itself  was  advanced  by  forcing  a  cylindrical  shield  of  steel 
plates  through  the  soft  mud.  The  shield  is  moved  by  twelve  hydraulic  jacks,  with  a  combined 
power  of  600  tons,  and  its  advance  packs  the  mud  so  tightly  that  it  is  readily  excavated  by  the 
workmen  within  the  shield. 

The  use  of  compressed  air  in  this  tunnel  is  two-fold.  As  in  all  caisson  work,  it  is 
necessary  to  constantly  replace  foul  air,  but  in  this  tunnel  it  is  also  necessary  to  employ  a  high 
pressure  to  aid  in  sustaining  the  walls  of  the  tunnel  during  construction.  The  air  pressure  is  there- 
fore over  three  atmospheres  (48  Ibs.)  In  this  pressure  the  workmen  are  able  to  remain  but  two 
hours  at  a  time — six  hours  constituting  a  day's  work,  of  which  four  hours  are  spent  in  the  tunnel 
and  two  in  the  atmosphere.  It  is  necessary  for  each  workman  to  be  examined  by  a  physician  before 
being  employed,  as  the  air  pressure  would  kill  any  but  the  most  robust.  Four  workmen  have  died 
from  the  effects  of  the  pressure,  due,  it  is  claimed,  to  carelessness  in  coming  too  quickly  from 
artificial  pressure  to  the  atmosphere.  The  change  is  made  by  means  of  air  locks.  The  lock  of 
which  a  section  view  is  given,  begins  in  a  brick  bulkhead  and  terminates  within  the  tunnel  entrance. 
It  is  ten  feet  high  by  five  and  a  half  feet  long.  Atmospheric  or  tunnel  pressure  is  secured  by  the 
usual  arrangement  of  pipes  and  stop  cocks,  readily  understood.  The  tunnel  advances  about  five 
feet  a  day,  and  is  now  nearing  completion. 


THE  AIR  LIFT  PUMP. 

THE  recently  patented  system  of  moving  fluids  automatically,   consists  of  an 
air  compressor  and  reservoir  to  contain  the  compressed  air,  the  needed  adjust- 
ing cocks,  foot  pieces,  and  the  tubing  to  convey  the  compressed  air  and  the 
water.     The  operation  of  the  pump  is  so  simple  that  it  can  be  understood  readily 
from  the  cut.     Compressed  air  is  led  into  the  artesian  well  and  is  liberated  into  the 
lower  end  of  the  water  pipe.     The  upward  movement  of  the  air  first  carries  up  all 
the  water  in  the  pipe  and  the  air  then  arranges  itself  automatically  in  layers  with  the 
water,  delivering  the  latter  at  the  surface.      The  compressed  air  is  said  to  form  a 
leakless  piston,   expanding  as  the  upward  pressure  diminishes,    which   completely 
dispenses  with  plunger,  rods,  bucket,  suction,  foot  and  discharge  valves.     In  fact, 
there  are  no  ordinary  pump  parts  whatever.     The  presence  of  mud,  sand,  and 
other  obstructions  usually  so  troublesome  to  pumping  machinery,  does  not  affect 
the  compressed  air  pump,  as  the  greater  power  supplied  forces  every  obstacle  to  the 
surface.      The  water  is  delivered  cooled  by  the  air  expansion,   and  thoroughly 
aerated. 

37 


THE  RELATION  OF  COMPRESSED  AIR  TO  THE  WATER  SUPPLY  OF  CITIES 
AND  TOWNS. — The  cut  showing  the  water  works  at  Wayne,  a  suburb  of  Philadelphia,  is  an 
interesting  exhibit  of  the  new  method  of  securing  water  by  means  of  scattered,  driven,  or  artesian 
wells,  operated  from  a  central  source  of  power  by  compressed  air. 

The  water  is  lifted  by  the  method  already  described  to  a  sufficient  height  to  allow  it  to 
run  back  to  the  compressor  house  by  gravity,  where  it  is  gathered  from  thirteen  different  wells,  in 
some  instances  2,000  feet  apart.  It  is  then  forced  by  special  means  through  the  distributing  pipes 
to  the  houses  of  the  town.  This  method  gives  life  and  sparkle  to  the  water,  and  oxidizes  the 
impurities  while  it  is  being  pumped.  The  effect  of  aerating  water  is  elsewhere  described  at  greater 
length.  (See  Aeration.) 

In  the  accompanying  cut  of  the  Wayne  Water  Works  is  shown  the  "picking  up"  of 
water  from  isolated  wells  in  both  high  and  low  ground.  In  the  low  ground  the  barrel  into  which 
water  is  delivered  by  the  air  pressure,  is  shown  as  resting  on  a  rough  structure  at  sufficient  height 
to  allow  the  water  to  run  back  to  the  station  house  by  gravity,  and  in  the  higher  ground  the 
barrel  is  shown  as  partly  buried.  The  air  pipe  and  return  water  pipes  are  not  shown,  being 
underground. 

Pumping  by  compressed  air  has  been  successfully  employed  at  Rockford,  111.,  where 
the  output  of  city  water  from  Artesian  wells  has  been  enormously  increased.  An  accompanying 
illustration  shows  part  of  the  Rockford  plant. 


39 


These  illustrations  show  two  views 
of  the  discharge  of  a  conduit  leading 
from  a  flowing  artesian  well  which  was 
increased  five-fold  in  its  discharge  by  the 
use  of  the  Air  Lift  Pump. 


THE  AUTOflATIC  PUMP. 

A  pump  operated  by  direct  air  pressure  has  been 
devised  to  force  water  from  wells  and  pits.  It  consists  of 
a  tank  with  an  air  valve  at  the  top  and  a  water  valve  at 
the  bottom.  The  water  rising  in  the  tank  carries  upward 
a  device  to  automatically  close  the  water  inlet  and  operate 
a  valve  by  which  compressed  air  is  admitted.  The 
pressure  thus  produced  forces  the  water  out  of  the  tank 
and  delivers  it  wherever  desired.  As  the  water  descends, 
a  device  at  a  certain  point  automatically  operates  the  air 
and  water  valves,  reversing  the  process. 

Recent  improvements  have  been  made  upon  the  old 
devices,  which  ensure  continuous  and  automatic  action 
and  allow  of  operation  until  the  water  is  entirely  exhausted 
from  the  swamp  or  pit  in  which  the  tank  is  placed. 

DRIVING  PUMPS  BY  COMPRESSED  AIR.— In 
most  mines  where  compressed  air  is  employed  to 
operate  drills,  this  power  has  been  substituted  for  steam 
in  driving  pumps.  A  mine  owner  recently  declared  that 
the  incidental  value  of  compressed  air  in  preserving 
timbers  and  walls,  was  alone  equal  to  the  value  of  steam. 


42 


THE  AIR  BRAKE. 

;  H1LE  there  are  several  systems  of  air  brakes,  the  perfected  compressed  air  brake  which 
is  in  most  general  use  on  railway  locomotives  and  cars,  is  the  Westinghouse  quick 
action   automatic  brake.      Compressed  air,    supplied  by   a   steam  engine   and 
compressor,  is  stored  in  a  main  reservoir  on  the  locomotive,  and  led  by  the  main  or 
brake  pipe  to  the  engineer's  brake  and  equalizing  discharge  valve,   and  thence 
along  the  train,  supplying  the  auxiliary  reservoir  on  each  car  with  air.     From  this  reservoir  the 
brake  cylinder  is  supplied  for  application  of  the  brakes. 

The  automatic  action  of  the  brake  is  due  to  the  construction  of  a  triple  valve,  which  is 
connected  with  the  main  train  pipe,  to  the  auxiliary  reservoir,  and  brake  cylinder.  It  is  operated  by 
the  variation  of  pressure  in  the  brake  pipe  (i)  to  admit  air  from  the  auxiliary  reservoir  (or  under  certain 
conditions  from  the  train  pipe)  to  the  brake  cylinder.  This  applies  the  brakes,  and  cuts  off  com- 
munication from  the  main  train  pipe  to  the  auxiliary  reservoir,  or  (2)  to  restore  the  supply  from  the 
train  pipe  to  the  reservoir,  at  the  same  time  letting  the  air  in  the  brake  cylinder  escape,  thus 
releasing  the  brakes. 

The  primary  parts  of  the  triple  valve  are  a  piston  and  a  slide  valve.  A  moderate 
reduction  of  air  pressure  in  the  train  pipe  causes  the  greater  pressure  of  the  air  stored  in  the  auxiliary 
reservoir  to  force  the  piston  of  the  triple  valve  and  its  slide  valve  to  a  position  which  will  allow  the 
air  in  the  auxiliary  reservoir  to  pass  directly  into  the  brake  cylinder  and  apply  the  brake.  A  sudden 
or  violent  reduction  of  air  in  the  train  pipe  produces  the  same  result,  and  in  addition  causes  supple- 
mental valves  in  the  triple  valve  to  open,  permitting  pressure  from  the  train  pipe  to  enter,  and 

43 


APPLICATION    OF   AIR    BRAKE   TO    RAILWAY    LOCOMOTIVES. 

augmenting  the  power  of  the  pressure  derived  from  the  auxiliary  reservoir  about  20  per  cent.,  pro- 
ducing instantaneous  action  of  the  brakes  at  their  highest  efficiency. 

As  soon  as  the  pressure  in  the  brake  pipe  is  restored  to  an  amount  in  excess  of  that 
remaining  in  the  auxiliary  reservoir,  the  piston  and  slide  valve  are  forced  back  to  their  normal 
position,  opening  communication  from  the  train  pipe  to  the  auxiliary  reservoir,  permitting  the  air  in 
the  brake  cylinder  to  escape  to  the  atmosphere,  thus  releasing  the  brakes.  If  the  engineer  desires  to 
apply  the  brakes,  he  moves  the  handle  of  the  engineer's  brake  valve  to  the  right,  which  first  closes 

44 


a  port,  retaining  the  pressure  in  the  main  reservoir,  and  then  permits  part  of  the  air  in  the  train 
pipe  to  escape.  To  release  the  brakes,  he  moves  the  handle  to  the  extreme  left,  which  permits  the 
air  to  flow  freely  from  the  main  reservoir  into  the  brake  pipe,  restoring  pressure  and  releasing  the 
brakes.  In  every  car  there  is  a  cord  which,  if  pulled,  opens  a  valve  in  the  brake  pipe  and  thus 
applies  the  brakes.  The  same  action  occurs  in  case  the  cars  accidentally  break  apart  from  each  other. 
The  automatic  application  of  the  brakes  by  any  reduction  of  pressure  in  the  train  pipe,  forms  one  of 
the  most  ingenious  and  effective  safeguards  in  modern  railway  appliances. 

In  the  safe  and  effective  operation  of  railroad  brakes,  compressed  air  stands  alone.  Until 
very  recently,  however,  its  use  has  been  confined  to  steam  railways,  but  the  increasing  employment 
of  trains  of  high  speed  electric  cars  has  required  the  use  of  the  air  brake.  At  the  recent  Columbian 
Exposition,  the  brakes  upon  the  Intramural  Electric  Railroad  were  operated  by  air,  which  was  com- 
pressed by  individual  pumps  on  each  train,  receiving  power  from  special  electric  apparatus.  The 


LOCOMOTIVE  TENDER,  SHOWING  APPLICATION  OF  THE  AIR  BRAKE  TO  CARS. 

45 


AIR  BRAKE  MOTOR  USED  UPON  THE  INTRAMURAL  R.    R.,  COLUMBIAN  WORLD'S  FAIR,  CHICAGO,  ILL. 


air  fixtures  were  similar  to  those  in  general  use  on  steam  locomotives,  but  in  place  of  steam  fixtures 
an  electric  motor  was  arranged,  operating  automatically.  Whenever  the  air  pressure  reached  60 
pounds  (the  pressure  carried)  it  became  sufficient  to  operate  a  rheostat  and  check  the  motor,  and 
when  sufficient  leakage  had  occurred,  or  the  use  of  the  brake  had  reduced  the  pressure,  the  motor 
started  again,  automatically. 

AIR  BRAKES  IN  STREET  CAR  SERVICE.— The  increasing  use  of  heavy  and  high 
speed  cars  in  street  car  service,  whether  the  motive  power  be  electricity  or  cables,  seems  to  make 
the  application  of  the  air  brake,  even  to  single  cars,  a  logical  necessity,  as  under  those  conditions 
the  manual  labor  and  attention  required  by  the  hand  brake  are  so  great  that  the  motorman  is  not 
able  to  keep  his  car  under  control  without  the  utmost  exertion.  The  principle  of  the  air  brake  has 
been  successfully  adapted  to  street  car  service.  The  air  is  compressed  by  attaching  an  eccentric  to 
the  axle  of  the  car.  About  forty  revolutions  suffice  to  fill  the  reservoirs  with  air  at  a  pressure  of  32 
pounds.  Having  attained  that  pressure,  a  governor  cuts  off  in  such  manner  that  the  piston  stops 
working  against  pressure,  and  operates  in  free  air  as  long  as  the  reservoir  gauge  indicates  32  pounds 
pressure.  The  motorman  applies  the  brake  by  simply  turning  the  controlling  valve,  and  but  three 
pounds  of  the  storage  pressure  are  required  for  each  application.  When  the  brakes  are  released  and 
the  car  is  started  again  the  piston  once  more  operates  against  pressure  to  restore  the  reservoir  pressure 
to  32  pounds,  but  by  an  automatic  arrangement  this  does  not  begin  until  the  car  has  gathered 
headway,  and  then  but  five  turns  of  the  wheel  are  required. 


47 


APPLICATION    OF   THE    AIR    BRAKE    TO 
STREET   CARS. 


COMPRESSED  AIR  SAFETY  APPLIANCES  FOR  RAILROADS. 

'HE  system  of  interlocking  switches  and  signals  recently  introduced  at  Buffalo,  N.Y.,  on 
the  Delaware,  Lackawana  and  Western  R.  R.,  at  its  crossing  of  the  Western  New 
York  and  Pennsylvania  R.  R.,  is  notable  for  its  dependence  upon  compressed  air 
solely  for  the  whole  operation  of  signalling  a  switching,  without  the  intervention 
of  any  intermediate  agency.  The  movement  of  a  lever  at  the  central  station 
admits  air  to  pipes  which  lead  directly  from  the  reservoir  to  the  cylinder  moving  the  switch  and 
signals.  One  set  of  pipes  leads  to  the  front  end  of  the  operating  cylinder  and  another  set  to  the 
rear  end.  The  illustration  shows  the  operating  cylinder  with  its  piston  rod  connected  with  the 
switch  bar,  with  suitable  interlocking  devices. 

In  this  illustration  the  switch  is  open,  and  air  has  been  admitted  to  the  rear  end  of  the 
operating  cylinder  by  means  of  the  pipe  7.  When  the  operator  changes  the  position  of  the  lever, 
the  air  is  exhausted  from  pipe  7  and  admitted  to  pipe  5  and  passes  to  the  forward  end  of  the 
cylinder,  and  the  piston  is  forced  backward  until  the  switch  is  closed.  Then  the  locking  bar  i 
drops  into  a  notch  in  the  connecting  rod  which  locks  the  switch  in  place.  This  operation  of  the 
locking  bar  operates  the  semaphore  controlling  valve  2.  This  valve  being  open  when  the 
switch  is  locked,  the  air  passes  through  it  to  the  semaphore  that  guards  the  switch  and  sets 
it  to  "  safety." 

In  the  reverse  operation  the  air  is  exhausted  from  the  pipe  5  and  turned  into  the  pipe  7. 
This  forces  the  piston  forward,  the  first  part  of  the  movement  forcing  a  wedged-end  bar  under  the 
locking  bar  i,  lifting  it  out  of  the  notch,  thus  closing  the  valve. 

49 


ALL   PNEUMATIC    RAILROAD    SAFETY    APPLIANCES. 


ALL  PNEUMATIC  RAILROAD 
SAFETY  APPLIANCES. 


UNIVERSITY 


The  continued  movement  of  the  piston  forces  the  switch  open.  The  signals  are  held  in 
"  safety  "  position  by  the  pressure  in  their  cylinder. 

When  the  pressure  is  released  a  counter  weight  draws  the  signal  back  to  "  danger."  It 
is  found  in  practice  that  a  comparatively  low  pressure  of  air  is  sufficient  for  operation  of  this  system 
and  the  low  pressure  is  thought  to  be  favorable  to  the  prevention  of  condensation  and  freezing. 

PARTLY  PNEUMATIC  SWITCH  AND  SIGNAL  SYSTEM.— The  operation  of  railway 
signals  and  switches  from  a  central  point  or  tower,  with  the  well-known  interlocking  features  of 
such  systems,  is  successfully  accomplished  by  compressed  air,  in  which  that  is  the  motive  power, 
controlled  by  small  valves,  which,  in  turn  are  controlled  by  electro-magnets.  This  method  has 
the  advantage  over  systems  operated  directly  by  heavy  levers,  and  rod  and  wire  connections, 
in  the  saving  of  manual  labor,  space  required  in  operating  towers,  and  having  no  practical  limit 
to  the  distance  away  a  switch  may  be  operated. 

The  air  compressing  plant  required,  is  a  steam  generating  boiler,  an  air  compressor, 
and  a  condensing  tank  through  which  the  air  must  pass  before  entering  the  main  air  pipe.  This 
deprives  the  air  of  moisture  which  it  may  have  had  originally,  or  collected  in  the  process  of 
compression,  and  prevents  its  accumulation  in  the  valves  and  cylinders  of  the  system,  where  it  might 
interfere  with  their  operation. 

Each  signal  blade  is  connected  directly  to  a  small  compressed  air  cylinder,  the  pressure 
to  which  is  controlled  by  a  small  valve,  and  the  air  supply  is  obtained  from  a  cylindrical  tank  placed 
at  the  foot  of  the  signal  post,  kept  stored  from  the  main  supply  pipe  ;  consequently,  all  signals 
have,  at  all  times,  the  full  pressure  of  compressed  air  right  at  their  cylinder  valves.  The  small  pot 
or  drilling  signals  are  connected  in  like  manner  to  a  small  cylinder,  and  operated  in  like  manner ; 

.52 


both  signals  standing  normally  at  "danger"  position  by  means  of  a  counter  weight  and  spiral  spring 
respectively,  and  held  at  "  safety  "  position  only  when  pressure  is  admitted  to  the  cylinders. 

The  switches  with  their  locking  attachments  are  controlled  and  operated  by  a  long 
double  acting  cylinder  secured  to  the  ties,  the  air  pressure  being  governed  by  a  valve  also  operated 
by  small  compressed  air  pipes  leading  from  another  small  controlling  valve  placed  directly  in  the  signal 
tower.  In  case  of  a  long  distance  between  the  controlling  and  cylinder  valves  the  small  compressed 
air  pipes  are  filled  with  water  in  summer  and  with  alcohol  or  some  non-freezing  liquid  in  winter, 
which  being  non-compressible  is  moved  like  a  solid  rod,  by  the  admission  of  the  air  upon  it,  and 
obviates  the  waste  of  air  otherwise  occuring  each  time  the  pipes  must  be  filled  and  released,  in 
operating  the  cylinder  valve.  Automatic  means  are  provided  for  restoring  the  loss  of  water  in  case 
of  leakage. 

The  controlling  valves  of  these  signal  and  switch  cylinders  are  operated  by  electro- 
magnets, connected  with  a  complete  electrical  indicating  and  interlocking  switch  board  located  in 
the  signal  tower,  where,  as  in  all  such  systems,  a  switch  cannot  be  thrown  until  it  is  fully  protected  by 
the  setting  of  the  proper  signals  first,  and  then  cannot  be  returned  to  place  until  the  train  that  has 
entered  upon  it  has  passed  over.  (See  cuts  of  switch  tower,  and  tracks.) 

All  these  operations  are  accomplished  by  the  movement  of  small  keys  which  instantly 
make  or  break,  as  desired,  the  electrical  circuits  controlling  the  compressed  air  cylinders  attached  to 
signals  and  switches,  which  in  turn  are  acted  upon  immediately  by  the  air  pressure. 

To  cite  one  example  of  operation  in  a  railroad  yard  tower  in  1 888,  the  highest  number  of 
movements  in  24  hours  was  i  ,500,  and  the  highest  number  in  one  hour  was  86,  operated  by  one  man. 


54 


THE  RAILROAD  GATE. 

The  use  of  compressed  air  for  raising 
and  lowering  the  gates  at  crossings  of  rail- 
roads is  now  generally  practiced.  It  is  a 
good  illustration  of  the  substitution  of  air 
power,  easily  carried  and  applied  at  many 
and  distant  points,  in  the  place  of  numer- 
ous mechanical  devices  liable  to  get  out  of 
order. 

The  cut  shows  the  operation  of  the 
system,  except  the  compressor,  which  may 
be  operated  by  hand  power  either  at  the 
time  the  gates  are  to  be  raised  or  lowered 
or  the  power  may  be  obtained  from  a 
reservoir  of  air  previously  compressed  and 
kept  on  storage. 

Another  cut  shows  this  system  applied 
to  the  protection  of  a  dangerous  crossing  of 


two  railroads,  where  the  gates  are  closed  upon  one  and  opened  for  the  passage  of  a  train  upon  the 
other,  by  an  interlocking  device,  making  it  impossible  for  the  operator  to  raise  the  gate  upon  one 
road  without  closing  that  upon  the  other. 


PNEUMATIC    RAILWAY   GATE    DETAIL. 


A.  Cap  of  hollow  post. 
AA.  Middle  section  of  post. 

AAA.  Bottom  section  of  post. 

B.  Gate  arm  casting. 
BB.  Cross  balance  casting. 

BBB.  Balance  weight  casting. 

C.  Chain  sector. 

CC.  Frictionless  bearing. 

D.  "  Up  "  cylinder. 

E.  "  Down  "  cylinder. 

F.  Piston  head. 
G.g.  Locks  with  latch. 

H.  Lock  diaphragm. 
I.  Piston  rod. 

L.  Waste  oil  pipe  and  drip  cock. 
M.  Chain  connecting  piston  rods. 
N.  Chain  sheaves. 
O.  Chains  from  piston  to  sector. 


P.  Piston  cross-head. 

R.  Main  air  pipe  connecting  "up"  cylinders 

in  two  posts. 

RR.  Main  air  pipe  from  "up"  cylinders  to  pump 
S.  Main  air  pipe  connecting  "  down  "  cylin- 
ders in  two  posts. 
SS.  Main  air  pipe  from  "  down  "  cylinder  to 

pump. 

T.  Tie  air  pipe  from  bottom  of  "up"  cylin- 
der in  one  to  bottom  of  "down  "  cylinder 
in  the  other  post. 

U.  Tie  air  pipe  from  bottom   of   "down" 
cylinder  in  one  to  bottom  of  "  up  "  cylin- 
der in  the  other  post. 
W.  Sidewalk  arm  casting. 
WW.  Sidewalk  arm  pivot. 
X.  Sidewalk  arm  half  gear. 
Y.  Bumper  with  spring. 


COMPRESSED  AIR  INTERLOCKING  RAILWAY  GATES  AT  THE  JUNCTION  OF  THE  C.  B.  AND  Q.  AND  CHICAGO 
STOCK  YARDS  R.  RS.,  CHICAGO,  ILL. 


USES  OF  COnPRESSED  AIR  IN  RAILROAD  SHOPS. 

O  useful  have  Compressed  Air  Hoists  proved  themselves  in  railroad  shops,  that  they 
are  now  extensively  employed  over  lathes,  planers,  drill  presses  and  other  tools, 
y\  and  greatly  facilitate  shop  work.  Some  are  permanent ;  others  are  provided  with 

*•&  overhead  radial  runs,  or  constructed  in  connection  with  overhead  railways,  the 

latter  permitting  the  use  of  the  hoist  in  loading  or  unloading  all  manner  of  freight.  These  hoists 
readily  handle  from  800  to  4,000  pounds  ;  occupy  but  little  room,  and  are  extremely  convenient. 
In  fact,  compressed  air  has  become  such  an  important  and  useful  adjunct  to  railroad  shops  and 
round-houses  that  few  are  now  without  it.  Engine  rooms,  shops,  and  in  many  cases  car  yards  are 
kept  thoroughly  piped,  in  order  to  equip  hoists,  or  other  compressed  air  appliances  wherever  required. 

These  hoists  have  proved  themselves  so  valuable  for  all  lifting  purposes  that  their  use  is 
rapidly  extending.  They  are  much  employed  in  cold  storage  warehouses  to  handle  sides  of  beef. 

Excellent  results  may  be  secured  with  a  small  compressed  air  plant.  One  superintendent 
of  railroad  shops,  reports  that  two  compressors  with  a  storage  capacity  of  about  90  cubic  feet,  suffice 
for  shops  caring  for  85  locomotives,  and  also  an  engine  house,  and  three  hoists  in  the  yard. 

Any  good  quality  of  hose  will  stand  moderate  pressure,  and  can  be  used  readily  when 
flexible  pipe  is  needed. 

The  use  of  hoists  in  shops,  both  from  below  (A)  and  overhead  (B)  is  clearly  shown  in 
the  cut.  Hoists  B  are  equipped  with  radial  or  track  runs. 

In  some  railway  shops  a  compressed  ?.:r  punch  is  in  operation,  employed  to  punch  holes 
in  portions  of  boiler  plates,  which  cannot  be  reached  by  an  ordinary  boiler  shop  punch.  Compressed 
air  jacks  are  also  in  constant  use  for  car  and  truck  work.  They  are  applied  directly  to  the  side 

59 


sill  of  the  car,  are  easily  handled,  and  require  no  overhead  structure  or  additional  apparatus.     One 
compressor  supplies  all  the  pressure  required  for  the  plant. 

Compressed  air  angle  iron  shears  are  also  in  constant  use.  The  only  difference  between 
the  latter  and  compressed  air  punches  is  the  actual  shearing  and  punching  parts,  the  frame  and 
upper  parts  for  each  being  the  same.  At  the  back,  a  cylinder  1 2  inches  in  diameter  is  mounted  in 
a  vertical  position  and  its  piston  rod  'is  attached  to  the  long  arm  of  a  horizontal  lever  above  it. 
The  cylinder  is  designed  to  receive  air  under  the  piston,  and  a  spring  on  the  piston  rod  returns 
the  parts  to  a  normal  position  after  the  stroke  is  accomplished.  The  upward  stroke  is  limited  by 
a  by-pass  port  in  the  side  of  the  cylinder. 


MINOR  USES  OF  COMPRESSED  AIR  IN  RAILROAD  SHOPS. 

INCREASING  HEAT. — Compressed  air  is  used  in  combination  with  gas  on  a  blow  pipe  to 
create  intense  heat  in  small  space.  It  is  especially  valuable  in  working  upon  inconveniently  located 
parts,  where  fires  cannot  be  built  nor  frames  removed. 

CLEANING  STEAM  PASSAGES. — In  many  railroad  shops  the  steam  passages  and  ports  of 
new  locomotives,  or  old  ones  that  have  been  repaired,  are  cleaned  by  compressed  air,  instead  of 
firing  up  the  locomotive  and  using  steam.  The  boiler  is  readily  filled  with  compressed  air  from  the 
shop  plant,  saving  time,  trouble,  dirt,  smoke  and  fuel.  The  same  plant  tests  all  parts  of  the  air 
brake  apparatus. 

FORCING  OIL  FROM  BARRELS. — Where  oil  barrels  cannot  be  conveniently  raised  to  the 
lank,  compressed  air  may  be  applied  to  the  surface  of  the  oil,  which  is  forced  out  through  a  hose, 

61 


the  open  end  of  which  lies  upon  the  bottom  of  the  barrel.  The  hose  passes  out  through  the 
bung,  at  which  point  it  is  covered  by  a  tapering  sleeve,  thus  keeping  the  bung  air  tight.  This 
operation  is  varied  to  drive  oil  from  barrels  through  hose  to  any  desired  point.  This  principle  is  now 
employed  by  one  of  the  sleeping-car  construction  companies  to  force  up  the  water  used  in  each  car, 
and,  in  consequence,  the  water  tanks  are  placed  beneath  the  cars.  A  connection  is  made  with 
the  compressed  air  tank  under  the  car  and  at  the  top  of  the  water  reservoir,  and  when  the  water- 
stop  cock  is  open,  the  pressure  of  the  air  on  top  of  the  water  forces  it  up.  It  is  more  satisfactory  to 
employ  a  reducing  valve  between  the  air  tank  and  water  reservoir,  the  air  pressure  being  too  great 
for  the  small  supply  of  water. 

CLEANING  CAR  CUSHIONS. — A  jet  of  air  applied  to  car  cushions  cleans  them  quickly  and 
completely,  and  is  found  to  be  a  great  saving  in  time  and  labor  over  the  old  method  of  beating. 
This  method  of  cleaning  is  also  frequently  applied  to  carpets  and  rugs,  and  is  widely  used  in  London, 
where  special  machinery  is  employed.  An  extra  price  is  obtained  in  that  city  for  the  careful  clean- 
ing of  expensive  fabrics,  made  possible  by  the  compressed  air  process.  This  use  of  air  is  being 
constantly  extended,  and  in  some  car  shops  cars  are  cleaned  entirely  by  the  application  of  air  pressure. 

SANDING  RAILS  FOR  LOCOMOTIVES  BY  COMPRESSED  AIR. — This  device  distributes  sand 
automatically  upon  the  rails  by  an  air  blast  which  is  put  in  operation  when  greater  adhesion  is 
required  between  the  driving  wheels  and  rails.  The  old  method  of  delivering  by  valve  and  lever 
frequently  resulted  in  too  much  sand  or  too  little,  in  consequence  of  which  trains  were  often  stalled. 

COMPRESSED  GAS  FOR  CAR  LIGHTING. — The  recent  improvements  in  railroad  and  street  car 
lighting  have  come  from  the  use  of  compressors,  enabling  the  storage  of  considerable  gas  in  small 
compass.  The  plant  required  is  a  small  gas  works  located  in  some  available  place,  with  pipes 

63 


SPECIAL    USES    OP  4j Ft  &&• 


to  the  car  yards.  The  plant  consists  of  a  furnace 
for  the  production  of  the  gas,  purifiers,  gas  holder, 
compressors  and  storage  tank.  From  the  latter 
the  gas  is  drawn  off  to  the  cars,  as  required. 

COPYING  LETTERS  BY  COMPRESSED  AIR. — 
The  application  of  air  to  a  copying  press 
(as  shown  in  the  accompanying  cut),  is  a  service- 
able device,  though  of  course  available  only 
in  the  presence  of  a  plant.  The  screw  of  a  copying 
press  is  removed  and  an  air  cylinder  of  two  inch 
brass  tubing  Is  substituted,  attached  to  the  original 
yoke  of  the  press.  The  platen  is  returned  by  a 
spiral  spring.  The  press  is  not  mutilated  in  the 
least. 

OTHER  MINOR  USES  OF  COMPRESSED  AIR  are, 
taking  the  place  ot  bellows  at  forges  and  rivet 
heating  machines,  thus  dispensing  with  the  ser- 
vices of  blacksmiths  ;  tripping  and  returning 
the  ram  of  hydraulic  presses  ;  a  grate  shaking  de- 
vice ;  an  apparatus  for  opening  a  furnace  door ; 
compressed  air  bell  ringer  motors  put  in  operation  by  a  touch  ;  and  drop  bottom  cars  ;  to  which 
should  be  added  the  general  advantage  of  abating  smoke,  smell,  dirt  and  heat. 


TJIUVSR31T7I 


COHPRESSED  AIR  LOCOMOTIVE. 

!OMPRESSED  AIR  offers  a  valuable  motive  power  in  mines  where  the  conditions  of 
ventilation  make  it  inexpedient  to  use  steam.  Mines  which  are  already  supplied  with 
compressors  for  ventilation  can  readily  adapt  their  existing  plant  to  the  pressure  required 
by  air  locomotives.  A  pressure  of  from  400  or  500  pounds  to  the  square  inch  is 
commonly  used.  A  compressed  air  locomotive  is,  in  fact,  but  a  storage  tank  on  wheels,  with 
engines  equipped  to  convert  the  tank  pressure  into  direct  motion  of  the  wheels. 

The  tank  is  made  of  steel,  with  seams  double  and  treble  riveted.  If  there  is  any  danger 
that  the  locomotive  cannot  carry  sufficient  power  to  perform  the  services  required,  arrangements  can 
easily  be  made  to  replenish  the  tanks  at  stated  parts  of  the  mine,  by  drawing  air  in  small  pipes  from 
the  distant  storage  reservoir  at  the  compressors.  By  this  simple  and  convenient  means  compressed 
air  can  be  conducted  long  distances  with  very  slight  loss  of  power. 

The  dimensions  of  the  locomotive  illustrated  herewith  are  :  Gauge,  3  feet;  cylinders, 
8  inches  by  12  inches;  drivers,  24  inches;  weight,  15,820  pounds.  Dimensions  of  reservoirs, 
R.  S.  233^  inches  by  13  feet  9^  inches;  L.  S.  233^  inches  by  16  feet  o%  inch.  Reservoir 
pressure,  600  pounds  per  square  inch  ;  working  pressure,  100  pounds  per  square  inch. 


66 


THE    COMPRESSED  AIR  LOCOMOTIVE. 


UNLOADING  CARS. 


\ 


A  dump  car  has  been  invented 
recently,  which  is  operated  by  com- 
pressed air  from  the  locomotive.  The 
air  is  supplied  through  an  air  cylinder 
and  piston  mounted  on  the  truck  frame 
of  each  car.  Two  air  pipes  lead  from 
the  train  pipe  to  the  dumping  cylinder, 
one  entering  at  the  top  and  the  other  at 
the  bottom.  The  piston  rod  is  coupled 
directly  to  the  body  of  the  car.  An 
upward  stroke  dumps  in  one  direction, 
a  downward  stroke  in  the  other.  When 
the  car  is  to  be  dumped  in  either  direc- 
tion the  piston  is  at  midstroke,  and  the 
car  is  in  a  level  position  ;  but  if  the  car 
is  to  be  dumped  on  one  side  only,  the 
piston  is  adjusted  to  be  at  the  bottom 
of  the  cylinder  when  the  car  body  is 
level.  A  ten-inch  cylinder  is  employed, 
and  with  80  pounds  pressure  the  up- 
ward push  is  9,984  pounds,  the  down- 
ward pull  7,808  pounds.  The  dumping 
piston  is  operated  from  the  locomotive, 
from  which  also  the  car  bodies  are 
locked  and  unlocked  at  will,  by  small 
compressed  air  cylinders  with  latch 
controlling  pistons  under  each  car. 


68 


Lifting  Rails. 

THE  compressed  air  hoist  hangs 
directly  over  the    slide    ways 
leading  to  the  mill  where  the 
battered  ends  of  therailsare  to 
be  cut  off.     Two  men  place  the  hand 
shaped  clutches  on  each  end  of  the  rail 
to  be  raised,   which  is  then   securely 
grasped  and  swung  free  at  will.     The 

;rogress  of  the  rail  is  readily  governed 
y  ropes.  This  method  of  lifting  rails 
is  about  three  times  faster  than  the  old 
way  of  rolling  them  off  with  tongs,  or 
bars  and  shovels,  and  the  possibility  of 
accident  is  eliminated. 


OQ 


STREET  RAILWAY  CARS  OPERATED  BY  COMPRESSED   AIR. 

OR  some  time  compressed  air  has  been  successfully  used  as  a  motor  for  street  railways 
in  Nantes,  France,  at  Nogent  near  Paris,  and  Berne,  Switzerland,  the  air  compressors 
at  the  latter  place  being  operated  by  water  power.  Each  motor  carries  a  storage 
pressure  of  350  pounds  at  Berne,  and  2,000  pounds  in  the  line  recently  established 
in  the  city  of  Paris  itself.  Other  lines  carry  varying  pressures  between  these  figures.  The  Nogent 
line  traverses  narrow  and  much  travelled  streets,  sharp  curves  and  grades.  Under  these  conditions 
the  most  apparent  features  of  the  Mekarski  compressed  air  system  there  used,  are  high  speed  when 
desired,  absolute  control  of  the  car,  an  abundance  of  power,  and  silent  action. 

In  Chester,  England,  a  tram-car  line  is  operated  by  compressed  air.  The  amount  of  air 
carried  is  50  cubic  feet.  To  refill  the  tank,  while  the  car  is  in  rapid  motion,  a  plow  blade  is 
dropped  which  lifts  a  cover  plate  with  grooves  in  its  lower  side.  The  groove  forms  a  guide  connect- 
ing the  car  attachment  with  device  for  letting  in  compressed  air.  In  this  way  the  tank  can  be 
charged  almost  instantly. 

In  any  discussion  of  the  street  railway  motor  problem,  it  must  be  admitted  that  while 
much  progress  has  been  made  during  the  last  five  years,  yet  a  perfectly  satisfactory  system  has  not 
yet  been  found,  especially  for  lines  not  doing  enough  business  to  warrant  the  erection  of  the  over- 
head system  of  conducting  the  power. 

While  it  is  true  that  all  eyes  are  turned  to  electricity  to  solve  the  problem,  it  is  more  than 
likely  that  another  agent  may  be  found  to  be  more  economical  and  reliable. 

The  cable  car  system  represents  an  immense  outlay  in  preparation,  and  constantly 

70 


subjects  the  passengers  to  a  distressing,  jerky  motion.  The  demand,  however,  for  a  system  which 
is  inexpensive  and  satisfactory,  is  increasing  with  the  enormous  expansion  of  towns  into  cities,  all 
over  the  country. 

By  the  compressed  air  system  cars  are  handled  easily,  and  quickly  ;  the  speed  varjes 
at  will,  from  three  to  twenty-five  miles  ;  stops  can  be  made  on  grades  and  curves  without  difficulty 
in  starting  again  ;  there  is  no  danger,  odor,  noise,  or  other  discomfort.  This  system  is  in  successful 
use  abroad  and  meets  the  approval  of  all  citizens  in  the  cities  and  towns  in  which  it  is  used. 

Some  work  has  been  necessary  in  order  to  adapt  it  to  American  roads,  and  with  these 
changes  it  seems  likely  to  prove  very  useful. 


72 


COMPRESSED    AIR    STREET    CAR,    NOGENT,    FRANCE. 


SHOP  TOOLS  OPERATED  BY  COHPRESSED  AIR. 

THE  recent  erection  of  a  large  machine  shop  in  St.  Louis,  with  air  as  the  only  power 
employed,  marked  a  great  advance  in  the  application  of  compressed  air. 


/ 


•a? 


I 


PLAN   OF   A   SHOP   OPERATED    BY   COMPRESSED   AIR. 

i,  Main  Air  Pipe  ;  2,  Branch  Pipes ;  3,  Engines  for  Large  Tools  ;  4,  Engine  for  small  Tools  ;  5,  Power 
Crane;  6,  Hand  Cranes;  7,  Forges;  8,  Hammer;  9,  Oil  Furnace  ;  10,  No.  5  "Bull  Dozer"  ;  n,  Punching  and 
Shearing  Machine;  12,  Cold  Saw;  13,  Tool  Room;  14,  Planer;  15,  Shaper;  16,  Horizontal  Boring  Machine;  17, 
Drill  Presses ;  18,  Milling  Machine  ;  19,  Jumper;  20,  Lathes;  21,  Lathe;  23,  Turret  Lathe;  24,  Benches;  25, 
Testing  Benches ;  26,  Stock  Room  ;  27,  Boring  Mill ;  28,  Tracks ;  29,  Pits  under  Tracks ;  30,  Planer ;  31,  Bending 
Roll ;  32,  Radial  Drill. 

From  the  smallest  tool  grinder  to  a  twenty  ton  crane,  air  is  the  motive  power.    A  55-horse 
power  compressor  operates  the  plant.    The  cost  of  installation  is  stated  to  be  about  equal  to  that  of  an 


74 


ordinary  steam  plant.  The  air  is  stored  in  a  reservoir  beside  the  power  house,  and  from  this  it  is  piped  over 
the  entire  plant.  In  the  machine  shop  the  piping  is  overhead  and  serves  each  tool  directly.  The 
larger  tools  have  their  own  engines,  located  against  the  nearest  wall,  or  at  the  base  of  the  machine. 
The  turning  of  a  cock  starts  the  engine,  and  the  same  movement  cuts  off  the  supply  of  air  when 
power  is  no  longer  required.  By  this  means  the  tools  are  constantly  in  readiness,  but  consume  no 
power  when  idle.  The  usual  wilderness  of  shafting,  expensive  both  in  maintenance  and  power 
consumption,  is  entirely  avoided  unless  the  very  small  tools  form  an  exception.  They  are  grouped 
and  run  by  one  engine,  in  consequence  of  which  a  little  shafting  is  required. 

The  use  of  compressed  air,  as  above  described,  permits  a  saving  of  from  15  to  20  per 
cent,  and  improves  the  light,  ventilation  and  temperature. 

THE  VALUE  OF  COMPRESSED  AIR  AS  COMPARED  WITH  HYDRAULIC 
POWER. — A  member  of  the  Manchester  (England)  Association  of  Engineers  recently  declared  that 
he  had  introduced  an  air  compressor  along  side  of  hydraulic  machinery  for  working  stoking 
machines  in  the  Manchester  Gas  Works,  and  found  the  first  cost  of  the  air  compressing  plant  less 
than  that  of  the  hydraulic  system,  and  that  it  was  more  efficient  and  economical  in  operation. 
The  machinery  in  the  Portsmouth  (England)  Dockyard  is  operated  by  compressed  air,  and  air  engines 
have  been  found  more  satisfactory,  and  less  liable  to  breakage,  than  those  operated  by  water. 


75 


RIVETERS  AND  STAY-BOLT  CUTTERS. 

IVETERS  operated  by  compressed  air  are  now  generally  used  in  bridge  construction  works, 
and  in  boiler,  machine  and  railroad  shops.  The  ease  and  economy  with  which  the  air 
riveter  is  handled  makes  it  decidedly  superior  to  steam  and  hydraulic  riveters,  in  using 
which  it  is  necessary  to  carry  the  work  to  the  machine,  a  requirement  always  incon- 
venient and  frequently  difficult. 

Riveting  by  hand  is  said  to  require 
three  men  and  a  boy  to  rivet  250  rivets  per 
day.  The  compressed  air  riveting  machine, 
operated  by  one  man  and  two  boys,  will  drive 
from  three  to  six  thousand  rivets  in  a  day. 

These  machines  are  substantially  con- 
structed. A  piston  rod  connects  two  levers  of 
different  length,  forming  a  reversed  toggle 
joint.  The  lower  ends  of  the  larger  links  are 
attached  to  fixed  centres  on  the  frame.  The 
end  of  the  central  short  link  is  attached  to  the 
ram,  into  the  lower  end  of  which  the  die  head 
is  secured.  By  this  latter  arrangement  any 
desired  change  in  the  distance  between  the 
dies  is  easily  effected.  The  ram  has  a  stroke 


of  3j£  inches.  These  machines  are  balanced  so  that  they  may  be  operated  either  vertically  or 
horizontally,  as  desired.  Air  pressure  of  60  or  70  pounds  is  employed.  Variations  of  this  machine  are 
used  for  channel-iron  bridge  work,  and  riveting  boilers  and  tanks. 

For  boiler  riveting,  the  machine  proper  consists  of  a  cylinder  with  a  hammerhead  or 
die,  attached  to  the  end  of  the  piston  rod,  capable  of  being  easily  changed  to  adapt  the  machine  to 
rivets  of  different  sizes.  The  valve  is  operated  directly  by  the  pressure  in  the  cylinder  and  so 

arranged  that  the  stroke  repeats 
itself  automatically.  Another 
cylinder  closes  the  long  ends 
of  the  bars  or  arms  and  enables 
the  operator  to  clamp  the  boiler 
plates  together  with  a  pressure 
of  2,000  pounds,  previous  to 
riveting,  thus  securing  much 
tighter  work. 

The  compressed  air  rivet- 
er has  largely  replaced  the  port- 
able hydraulic  riveter,  as  the  use 
of  air  at  60  pounds  pressure  is  so 
much  more  convenient  than  that 
of  water  under  2,500  pounds,  as 
the  latter  requires  cumbrous  irou 

78 


pipes  especially  jointed.  This  riveter  is  a  valuable  addition  to  railroad  shops,  where  it  is  estimated 
that  one  gang  of  men  with  a  compressed  air  riveter  can  do  the  work  of  four  gangs  working  by 
hand.  A  truck  can  be  riveted  complete  in  twenty  minutes. 


STAY-BOLT  CUTTER. 

A  Stay  Bolt  Cutter,  which  does  the  work 
of  twenty  men,  is  in  use  in  several  railroad 
shops,  the  motive  power  being  compressed  air. 
The  nippers  are  operated  by  the  wedge  action 
of  the  bevelled  end  of  the  cross  head  of  the 
piston  cylinder.  This  remarkable  machine 
cuts  off  several  hundred  bolts  an  hour  and 
though  operated  so  rapidly,  there  is  no  jar  or 
loosening  of  the  bolts.  70  pounds  pressure  is 
sufficient  to  cut  off  one  and  a  quarter  inch 
bolts. 


DETAIL  OH  STAY-BOLT  CUTTER. 


COMPRESSED  AIR  CRANES. 

HAT  machine  shop  is  best  constructed  which  permits  the  use  of  travelling  cranes 
along  the  center  of  the  shop,  and  its  entire  length.  In  this  way  the  machines  on 
each  side  are  easily  and  quickly  served.  The  compressed  air  in  shop  cranes  is 
stored  in  a  cylindrical  reservoir  standing  on  the  car  (as  shown  in  the  accompanying 
cut)  and  also  in  three  horizontal  tubes  at  the  upper  part  of  the  crane.  The  interior 
of  mast  and  jib  is  also  used  as  storage  space.  The  main  reservoir  of  the  shop  crane  shown,  is  42 
inches  in  diameter  and  6  feet  high,  the  diameters  of  the  mast  and  jib  are  13  and  10  inches.  The 
total  storage  capacity  is  85  cubic  feet.  The  crane  is  propelled  by  a  pair  of  horizontal  engines, 
connected  with  a  front  axle  by  grooved  friction  gearing.  The  lifting  capacity  is  four  tons. 

OVERHEAD  COMPRESSED  AIR  TRAVELLING  CRANES,  as  shown  in  the  accom- 
panying cut,  possess  the  advantage  of  extreme  simplicity.  The  length  of  travel  is  about  400  feet, 
capacity  20  tons,  air  pressure  about  100  pounds.  These  cranes  are  easily  repaired,  easily  controlled, 
noiseless  and  moderate  in  cost. 

The  air  storage  capacity  is  sufficiently  generous  to  admit  of  considerable  use  without 
replenishing.  Crane  capacities  vary  from  one  to  one  hundred  tons.  The  speed  of  hoisting  varies 
from  five  to  forty  feet  a  minute,  and  trolley  travel  and  bridge  travel  from  25  feet  to  100  feet,  and 
50  inches  to  200  inches,  per  minute  respectively. 

Compressed  air  is  now  claimed  to  be  the  best  motive  power  for  shop  cranes  of  any  kind. 
The  air  compressor  required  to  operate  them  needs  little  attention,  as  the  pressure  of  air  in  the 
receiver  governs  the  compressor,  and  the  air  can  be  stored  in  any  convenient  part  of  the  building. 

80 


. 


OVERHEAD  TRAVELLING  CRANE.   M 


COMPRESSED   AIR  TOOLS. 

OMPRESSED  air  is  now  successfully  applied  to  tools  of  all  kinds,  from  the  roughest 
chisel  to  the  most  delicate  instrument  for  carving.  The  operation  of  the  tool  is  very 
simple  and  effective  and  the  extraordinary  results  accomplished  are  due  to  the  multitude 
and  uniformity  of  blows  which  are  struck  while  the  machine  is  in  operation.  Air  is 
forced  into  a  reservoir  by  an  air  compressor,  and  from  it  a  small  tube  leads  the  air  into  the  end  of  a 
cylinder  which  is  held  and  guided  by  the  workman.  In  tools  of  ordinary  size,  the  cylinder  is  about 
as  large  as  a  chisel  handle.  The  air  is  led  under  a  jacket  on  the  cylinder  to  a  valve  by  which  it 
reaches  the  piston.  Each  advance  of  the  piston  strikes  a  spindle  on  the  end  of  the  tool,  forcing  it 
outward,  the  return  motion  being  imparted  by  a  spring.  The  blow  of  the  piston  is  then  repeated, 
and  it  is  claimed  that  they  number  ten  thousand  a  minute.  A  large  number  of  compressed  air  tools 
is  used  in  the  shipyards  of  Cramp  &  Sons,  the  calking  on  war  ships  and  other  vessels  being  done 
wholly  by  these  instruments.  One  compressed  air  calker  does  the  work  of  four  men.  This 
ingenious  tool  has  been  adapted  to  many  uses.  It  is  effective  in  calking  boilers,  water  pipes  and 
tanks,  as  well  as  ships  ;  heading  tubes  of  boilers,  dressing  steel  castings,,  chipping  cast  and  wrought 
iron  work,  and  also  in  lettering,  carving  and  moulding  granite,  marble,  onyx  and  other  stones. 

This  tool  has  found  a  large  field  of  usefulness  in  dressing  granite  for  building  and 
monumental  purposes.  In  that  industry  modern  ingenuity  has  offered  so  far  no  improvement  over 
the  mallet  and  chisel  of  our  ancestors,  but  a  machine  has  been  constructed  which  fully  meets  the 
stone  cutter's  requirements.  A  hollow  iron  post  on  wheels  holds  a  nicely  balanced  movable  frame, 
on  one  end  of  which  is  a  compressed  air  tool  weighing  about  50  pounds,  and  of  great  power.  The 

83 


COMPRESSED  AIR  TOOL  FOR  DRESSING  GRANITE. 


entire  machine  is  substantially  constructed,  and  fitted  so  that  it  can  be  adjusted  easily  to  any 
position.  It  can  dress  a  square  foot  of  granite  in  eight  minutes,  a  task  which  would  require  one 
and  one-half  hours  of  hand  labor. 

To  operate  these  tools,  air  pressure  of  60  to  80  pounds  is  required.  In  addition  to  an 
extraordinary  saving  of  labor  in  every  instance,  the  absolute  evenness  of  the  blow  delivered  by 
these  tools,  produces  better  results  than  that  of  the  most  skilful  hand  labor. 

Detail  of  Compressed  Air  Tool. 


i.— Throttle  Nut.  2.— Throttle.  3.— Jacket.  4.— Piston.  5.— Split  Washer.  6.— Cylinder. 

7. — Washer  Sleeve.  8. — Compound  Spring.  9.— Nose.  10. — Spindle. 

85 


OPERATING  CLOCKS  AND  ENGINES  IN  PARIS. 

IN  1870,  a  system  of  operating  clocks  by  compressed  air  was  instituted  in  Paris,  France. 
A  small  central  station,  equipped  with  a  compressor,  was  established  in  the  Rue  St. 
Anne,  and  the  clocks  in  the  system  were  operated  from  this  by  pulsations.  The 
business  grew  slowly  at  first,  but  within  the  last  few  years  has  increased  with 
extraordinary  rapidity.  The  original  station  becoming  inadequate,  an  elaborate  and  powerful  plant 
was  established  in  the  suburbs  of  the  city  (Belleville)  and  from  this  upwards  of  10,000  clocks,  public 
and  private,  are  now  driven,  all  regulated  from  a  standard  clock  in  the  Rue  St.  Anne.  The  operation 
of  the  clocks  was  originally  the  main  object  of  the  system,  but  extensive  as  that  now  is,  it  forms 
but  a  small  part  of  the  usefulness  of  compressed  air  in  Paris.  This  power  is  obtainable  anywhere 
in  the  city,  subject  to  a  meter,  like  gas,  and  can  thus  be  used  in  large  or  small  quantities,  for  driving 
engines  and  tools.  At  the  central  station  a  series  of  engines  drive  a  great  number  of  air  compressors, 
generating,  it  is  said,  10,000  horse  power.  The  air  is  drawn  in  direct  from  the  engine  h~use,  at  a 
temperature  of  70  degrees  and  compressed  to  75  pounds.  It  is  then  led  about  the  city  in  mains, 
which  are  laid  beneath  the  streets  and  along  the  soffit  of  the  famous  Paris  sewers.  The  mains  are 
of  cast  iron,  each  length  having  plain  ends,  connected  by  an  external  joint  of  air  tight  India  rubber 
packing  rings.  This  permits  a  little  play  and  assures  a  minimum  leakage.  The  meter  is  a  small 
double  cylindrical  box.  The  air  passes  by  a  branch  through  the  botton  of  the  inner  box,  up  through 
it,  and  down  outside  between  the  two  boxes,  and  away  through  a  branch  at  the  bottom  opposite 
the  entrance.  The  measuring  apparatus  is  a  little  six  armed  fan  with  nickel  or  aluminum  vanes 
placed  near  the  bottom  of  the  inner  casing  and  communicating  motion  to  clock  work  mechanism 


outside  which  records  the  number  of  revolutions.  A  reducing  valve  and  a  small  heater  for  the 
motor  are  the  only  other  needed  parts.  The  heater  is  used  to  economize  air  by  expanding  it.  It 
has  been  found  in  Paris  that  by  using  heated  air  the  mechanical  efficiency  of  the  motor  is  much 
increased.  When  refrigeration  is  required,  however,  the  air  is  not  heated,  in  order  to  avail  of  the 
cooling  due  to  expansion. 

The  application  of  compressed  air  which  the  Paris  system  permits,  is  as  Varied  as  the 
requirements  for  power.  In  many  parts  of  the  city  this  convenient  and  inexpensive  power  is  used 
to  run  the  dynamos  to  generate  electricity  for  lighting  and  other  purposes. 

The  value  of  the  system  is  apparent.  There  is  an  absence  of  danger,  and  annoyance, 
a  saving  of  space,  reduction  of  insurance,  and  incidentally  is  derived  the  very  important  advantage 
of  pure  and  cool  air,  the  value  of  which,  in  some  cramped  shops,  can  scarcely  be  exaggerated. 

It  has  recently  been  demonstrated  for  the  French  government  that  in  case  of  a  siege  of 
the  city  of  Paris,  the  application  of  half  the  compressed  air  now  being  generated,  to  refrigerating 
food,  would  preserve,  at  a  temperature  below  freezing,  a  sufficient  supply  of  food  to  last  six  months. 


COAL  niNING  MACHINES  OPERATED  BY  COflPRESSED  AIR. 

i]T  was  long  believed  that  machinery  could  not  compete  in  coal  mines  with  a  pick  axe, 
but  within  the  past  decade  coal  mining  machines  operated  by  compressed  air  have 
come  into  general  use,  especially  in  mining  bituminous  coal.  Of  these  machines,  one 
(illustration  A)  is  small,  strong  and  easily  operated.  It  is  from  five  to  seven  feet  long, 
two  feet  high  and  two  feet  wide.  It  has  no  complicated  parts,  and  reduces  friction  and  power 
consumption  to  a  minimum.  Two  men  are  required  with  each  machine,  one  to  operate,  and  a 
helper  to  shovel  away  cuttings.  The  machine  is  mounted  on  a  platform,  so  pitched  in  front  of  the 
coal  that  the  recoil  is  neutralized  by  gravity.  The  pick  strikes  from  200  to  210  blows  a  minute, 
and  as  it  works  under  the  coal  the  runner  allows  the  machine  to  run  forward  down  the  platform, 
and  swings  the  pick  from  side  to  side  in  its  progress.  The  amount  of  compressed  air  required  is  but 
ten  cubic  feet  per  minute,  delivered  at  a  pressure  of  75  pounds,  which  can  easily  be  drawn  in  small 
pipes  for  a  mile  or  more  with  very  slight  loss  of  power.  This  machine  weighs  about  500  pounds. 
Another  machine  (illustration  B)  consists  of  a  bed  frame,  two  feet  wide  by  seven  and  a  half  feet 
long,  composed  of  two  steel  channel  bars  firmly  braced,  the  top  plates  on  each  forming  racks  with 
their  teeth  downward,  into  which  the  feed  wheels  of  the  sliding  frame  engage.  This  sliding  frame 
consists  mainly  of  two  steel  bars.  At  the  rear  of  this  frame  a  double  engine  is  mounted,  from 
which  power  is  transmitted  to  the  rack,  by  means  of  which  the  sliding  frame  is  fed  forward.  At 
the  front  end  is  the  cutter  bar.  This  contains  steel  bits,  held  in  place  by  set  screws.  When  the 
cutter  bar  is  revolved  these  cutters  or  bits  cover  its  entire  face.  The  cutter  bar  is  revolved  by  an 
endless  curved  link  steel  chain,  and  advances  mechanically  as  described. 


SIDE     VIEW  -CUTTER     BAR     PARTLY     EXTENDED. 


This  machine  requires  an  operator  and  helper.  It  is  taken  into  the  mine  on  trucks, 
placed  upon  two  boards  in  front  of  the  coal  and  braced  by  front  and  rear  jacks.  The  cutter  bars 
range  in  length  from  39  to  48  inches,  and  after  a  full  cut,  the  bar  is  withdrawn  by  reversing  trie 
engine.  It  is  claimed  that  this  machine  can  cut  1 50  lineal  feet  face  to  a  depth  of  6  feet  in  ten 
hours. 

The  advantages  derived  from  operating  coal  mining  machines  by  compressed  air  are  said 
to  be  economy,  better  condition  of  coal,  concentration  of  work,  and  absolutely  no  danger 
from  sparks. 


THE  COMPRESSED  AIR  GUNS  OF  THE  CRUISER  VESUVIUS. 

HERE  is  no  explosive  on  board  the  Vesuvius  but  the  gun  cotton  projectiles  which  are 
intended  to  annihilate  the  enemy.  The  power  that  is  capable  of  hurling  these  deadly 
missiles  more  than  a  mile  with  extraordinary  accuracy,  is  air.  The  Vesuvius  is  an 
unarmored  cruiser  of  950  tons  and  4,000  horse  power.  She  is  252  feet  in  length,  and 
has  a  record  of  2 1  ^  knots.  These  facts  though  interesting  are  unimportant,  and  the  title  of  the 
Vesuvius  to  fame  lies  in  the  three  stationary  so  called  pneumatic  dynamite  guns  which  project 
above  the  deck.  These  guns  are  unique  and  extraordinary.  Each  is  55  feet  in  length,  and 
composed  of  two  sections.  The  upper  half  is  immovable,  but  the  lower  section  can  be  detached 
and  dropped  to  a  horizontal  position,  where,  in  connection  with  a  cylinder  which  then  lies  directly 
in  front  and  in  contact,  this  lower  section  resembles  a  huge  revolver.  Like  an  ordinary  revolver, 
the  cylinder  turns,  and  is  composed  of  chambers,  five  chambers  in  each  cylinder  and  two  cylinders 
for  each  gun. 

To  load  a  gun,  the  lower  section  is  dropped.  It  then  receives  a  cartridge  from  its 
cylinder  by  a  mechanical  adjustment,  and  is  reconnected.  At  the  bottom  of  the  gun  is  the 
compressed  air  chamber  which  forms  the  impelling  force,  pressure  of  about  i  ,000  pounds  being 
employed.  As  the  guns  are  immovable  and  point  straight  from  the  bow,  the  aim  is  produced  from 
the  steering  gear.  This,  with  the  three  levers  which  discharge  the  guns,  are  in  a  conning  tower 
which  can  be  entered  only  from  below  deck. 

The  projectile  weighs  from  400  to  1,000  pounds,  the  bursting  charges  being  from  200 
to  500  pounds  of  gun  cotton  or  explosive  gelatine.  The  explosive  contained  in  it  is  discharged  by 

9' 


a  cap  which  is  ignited  by  contact  with  either  the  solid  target  or  the  water.  The  aim  is  to  have  the 
shell  strike  the  water  just  short  of  the  target  and  explode  after  it  has  entered  the  water  to  a  depth 
of  i  o  to  15  feet.  The  chief  dependence  for  successful  action  is  against  the  under  water  hull  of  the 
enemy's  ship.  A  perforation  here  is  likely  to  prove  fatal.  The  guns  are  fixed  in  ship  at  an  angle 
of  1 8  degrees.  The  range  is  varied  by  either  varying  the  cut  off  of  the  automatic  valve  or  by 
varying  the  pressure  used.  The  range  of  each  tube  is  one  mile  for  a  shell  carrying  500  pounds  of 
explosives,  and  3,000  yards  for  a  shell  containing  200  pounds  of  explosives,  and  within  that,  the 
distance  which  the  shell  is  to  traverse  can  be  accurately  adjusted  by  gauging  the  air  pressure. 
On  leaving  the  gun  the  projectile  ascends  sharply  to  a  height,  and  then  describing  a  curve, 
plunges  at  length  sharply  downward.  Frequent  tests  have  demonstrated  that  for  stationary  firing 
at  a  stationary  object,  the  accuracy  of  range  is  remarkable. 

THE  COMPRESSED  AIR  TORPEDO  GUN  for  sea  coast  defence  is  mounted  in  a  similar  manner 
to  the  ordinary  sea  coast  gun,  being,  unlike  the  guns  of  the  "  Vesuvius,"  movable  both  for  elevation 
and  training.  The  guns  are  fifty  feet  in  length.  Air,  compressed  to  i  ,000  pounds  per  square  inch,  is 
used  as  the  propelling  charge.  Five  1 5-inch  guns  are  to  be  mounted  at  Sandy  Hook  and  San 
Francisco  for  experiment.  These  guns  can  throw  a  shell  charged  with  500  pounds  of  high  explosive 
a  range  of  one  mile,  a  shell  with  200  pounds  bursting  charge  to  a  range  of  3,000  yards,  and  one 
containing  100  pounds  to  a  range  of  4,500  yards,  an  automatic  valve  admitting  the  air  to  the  gun 
bore  and  making  the  cu'  off  at  any  desired  point,  so  that  without  changing  the  elevation  a  projectile 
may  be  dropped  just  out  of  the  muzzle,  or  sent  to  the  extreme  range.  The  importance  of 
compressed  air  in  naval  warfare  has  been  shown  recently  in  the  purchase  of  the  passenger  steamer 
"  El  Cid,"  and  her  equipment  as  the  Brazilian  Government  cruiser  "Nictheroy."  The  principal 

94 


feature  of  the  armament  was  one  of  the  movable  compressed  air  guns  above  described.  An  opening, 
shaped  like  a  horse  shoe,  was  cut  in  the  upper  deck  at  the  bow  of  the  ship,  and  a  heavy  well- 
shaped  base  was  erected  below.  Upon  this  the  great  air  gun  was  mounted.  A  powerful 
three-stage  compressor,  located  just  behind  the  ships'  engine  room,  supplied  compressed  air  at  a 
pressure  of  i  ,000  pounds,  the  compressor  being  capable  of  doubling  the  pressure  if  desired.  The 
air  was  led  in  heavy  piping  to  a  reservoir  in  the  bow.  Practice  firing  with  the  gun  showed  excellent 
results.  The  projectile  is  a  cylinder  containing  gun  cotton.  This  explosive  is  used  because  by 
keeping  it  wet  it  is  perfectly  harmless,  and  it  can  be  dried  out  as  desired  for  use.  The  method  of 
exploding  is  either  by  impact,  time  fuses,  or  miniature  electric  batteries  in  each  projectile.  The  latter 
method  of  discharge  is  regarded  with  much  favor.  The  jar  in  starting  the  projectile  from  the  gun, 
liberates  the  acid  into  the  miniature  cup.  Electricity  is  thus  generated,  and  the  fine  thread  of 
platinum  is  soon  heated  red  hot.  This  acts  as  the  spark  within  the  cartridge  and  explosion 
follows  without  fail,  and  wherever  the  projectile  has  fallen. 

The  result  of  this  bold  experiment  in  naval  armament,  is  being  watched  with 
interest.  The  success  of  the  "Nictheroy"  means  nothing  less  than  a  revolution  in  naval 
construction.  It  is  only  fair  to  state,  however,  that  the  vessel  was  hastily  transformed  from  a 
merchant  vessel,  and  that  the  time  occupied  in  equipment  was  only  about  one  month.  If  the 
experiment  of  throwing  explosives  by  this  system  should  prove,  in  this  instance,  even  a  moderately 
successful  method  of  sea  warfare  then  much  might  be  expected  from  a  system  having  proper 
elaboration  and  operated  by  a  properly  trained  crew. 

DISAPPEARING  GUN  CARRIAGES  are  operated  successfully  by  compressed  air.  The  recoil  of 
the  gun  is  overcome  by  using  a  compressed  air  buffer,  in  which  the  air  pressure  is  575  pounds. 

95 


The  accompanying  illustrations  are  from  instantaneous  photographs,  and  show  this  gun 
in  the  act  of  being  discharged — the  projectile  being  caught  in  the  act  of  flight.  It  should  be  under- 
stood that  these  cuts  are  prepared  by  the  photo-engraving  process  direct  from  the  photograph, 
and  without  alteration  or  re-touching  of  any  kind.  Their  interest  is  unique,  and  may  be  depended 
upon  as  authentic. 

The  lower  picture  shows  the  gun  entire  with  the  projectile  at  the  extreme  upper  left- 
hand  corner  of  the  picture.  The  upper  picture  shows  the  muzzle  of  the  gun  only,  with  the  projectile 
but  a  small  distance  from  it. 

The  projectile  here  shown  is  of  15"  diam.  x  10  ft.  extreme  length.  Its  weight  is 
1,100  Ibs.  and  it  carries  500  Ibs.  of  explosive  gelatine.  Its  range  of  flight  is  2,400  yards  and  the 
velocity  at  the  moment  in  which  the  picture  was  taken,  was  between  500  and  600  ft.  per  second. 
It  carries  the  latest  pattern  of  fuse,  which  has  overcome  all  former  difficulties.  Its  action  is  purely 
mechanical  and  is  brought  about  by  the  shock  due  to  the  discharge  of  the  gun  and  that  due  to  the 
impact  of  the  projectile  against  the  target  or  water.  Both  these  shocks  are  required  to  act  in 
succession,  in  order  that  the  fuse  may  act  and  the  shells  be  exploded.  This  construction  gives 
practically  absolute  security  in  the  handling  of  the  projectile,  as  no  single  shock  of  any  kind  is 
able  to  explode  it. 

It  may  be  added  that  the  plant  of  guns  at  Sandy  Hook,  N.  ].,  when  tested  under  the 
rigid  requirements  of  the  U.  S.  Army,  surpassed  those  requirements  in  every  item — accuracy  of  fire, 
extreme  range,  number  of  shots  per  hour  and  certainty  of  explosion  on  impact.  The  photographs,  of 
which  these  pictures  are  a  reproduction,  were  made  during  the  official  test  of  July  and  August,  1893. 


SNAP  SHOTS  AT  THE 
DYNAMITE  GUN. 


SHOWING    PROJECTILE    IN 
FLIGHT. 


HOISTING    THE    COMPRESSED    AIR    GUN    INTO    PLACE    ON    THE    NICTHEROY. 
(From  photograph  made  by  the  Chapman  Derrick  Wreckage  Co.) 


THE  "  DESTROYER." 

HE  propulsion,  both  above  and  below  the  surface,  ot  projectiles  containing  high 
explosives  has  become  one  of  the  serious  problems  of  modern  war-ships,  and  of 
defence  construction.  The  "  Destroyer,"  known  as  a  detachable  ram,  is  the 
result  of  many  years  of  thought  and  labor  on  the  part  of  the  late  Captain  John 
Ericsson,  the  famous  inventor  of  the  "Monitor."  The  "Destroyer"  is  130  feet  in  length, 
with  12  feet  beam.  Her  displacement  is  250  tons  ;  draught,  10  feet.  Bow  and  stern  lines  are  the 
same,  straight  and  exceedingly  sharp.  The  gun  is  constructed  of  steel,  with  breech  mechanism 
similar  to  that  in  high  power  guns.  The  caliber  is  1 6  inches,  length  32  feet.  The  gun  ends 
at  the  bow  of  the  vessel,  and  the  end  of  the  projectile  extends  beyond  the  bow,  but  is  eight 
feet  underwater.  The  projectile  is  also  made  of  steel,  is  27  feet  long,  16  inches  in  diameter, 
and  weighs  1,525  pounds.  At  the  front  of  it  is  the  explosive,  which  is  one-fifth  of  the  entire 
weight,  and  is  discharged  by  a  percussion  cap.  The  projectile  is  made  in  three  sections,  for 
convenience  in  handling. 

In  loading,  the  breech  of  the  gun  is  opened,  and  the  torpedo,  placed  on  a  carriage,  is 
run  into  the  bore  of  the  gun,  and  close  to  the  tail  end  of  the  torpedo  comes  the  piston,  then  the 
tail  rod,  through  which  runs  the  electric  wire  used  in  firing,  and  last  the  powder  can,  containing 
from  20  to  40  pounds  of  powder.  The  breech  is  then  closed  ;  the  valve  that  supplies  the 
compressed  air  is  opened,  and  with  a  pressure  of  40  pounds  to  the  square  inch,  the  torpedo  is  forced 
to  its  final  firing  position. 

The  initial  pressure  in  the  gun  when  fired  is  4,000  pounds  per  square  inch,  and  the 


muzzle  velocity  is  548  feet  per  second.  Upon  reaching  the  water,  the  piston  falls  off ;  a  piston  is 
thus  lost  with  each  shot. 

Immediately  after  the  discharge  of  the  projectile,  the  valve,  which  has  hung  above  the 
cone  of  the  projectile,  and  which  is  opened  by  a  rod  from  the  compressor,  is  shut  down  over  the 
muzzle  of  the  gun.  The  gun  is  then  drained  and  is  ready  for  another  shot. 

It  should  be  noted  that  the  manner  of  exploding  the  powder  charge  in  a  large  air  space 
filled  with  compressed  air,  is  a  radical  departure  from  the  ordinary  usage.  This  is  claimed  by  the 
owners  to  be  of  great  advantage,  as  the  air  not  only  forms  a  cushion,  but  adds  to  the  efficiency 
of  the  combustion  of  the  powder. 

It  is  claimed  that  recent  experiments  with  the  "  Destroyer"  have  demonstrated  that  it 
is  possible  to  fire  a  sub-marine  torpedo  accurately  a  distance  of  600  feet.  To  that  distance  the 
vertical  danger  space  is  22  feet,  and  the  lateral  accuracy  is  sufficient  to  hit  a  vessel  50  feet  long. 


THE  DESTROYER-  UytRlOROr  BOW  SHOWING  COMPRC^IRGUNANO  PROJLCTlLf 


LOCOflOTIVE  TORPEDOES. 

HE  Whitehead  Torpedo  is  now  regarded  as  such  a  successful  implement  of  war  that  it  has 
been  generally  adopted  by  European  nations.  This  torpedo  is  propelled  by  compressed 
air.  Its  length  varies  from  12  to  19  feet,  its  diameter  from  13  to  15  inches.  The 
torpedo  on  being  discharged  will  travel  at  any  length  according  to  adjustment,  at  a 
uniform  speed  of  24  knots  for  600  yards.  Having  reached  the  end  of  its  travel  without  impact,  it 
will  either  sink  or  rise  as  previously  adjusted.  The  foremost  compartment  contains  from  50  to  100 
pounds  of  gun  cotton.  Upon  striking  a  ship,  this  charge  is  fired  by  a  pistol  which  screws  into  the 
nose  of  the  torpedo.  The  point  of  the  pistol  is  driven  in  by  compact  forcing  the  point  of  a  steel 


THE  WHITEHEAD  TORPEDO. 
I O2 


striker  into  a  detonator.  A  large  portion  of  the  torpedo  is  devoted  to  an  air  reservoir,  within  which 
compressed  air  is  carried  to  a  pressure  of  i  ,000  pounds.  This  operates  a  three  cylinder  engine 
driving  two  propellers  revolving  in  opposite  directions  in  the  tail  of  the  torpedo.  The  mechanism 
in  the  balance  compartment  works  two  exterior  rudders,  which  keeps  the  torpedo  at  a  uniform 
depth.  This  mechanism  constitutes  the  secret  of  the  invention  and  is  sold  with  the  right  to 
manufacture  the  torpedo.  The  discharge  is  secured  from  a  compressed  air  gun  and  may  occur 
above  or  below  water.  This  torpedo  is  owned  and  made  in  Austria.  It  is  estimated  by  the  United 
States  Navy  that  each  torpedo  costs  about  $i  ,000. 

The  Navy  has  purchased  the  right  to  manufacture  the  torpedo,  and  they  are  made  in 
Brooklyn,  N.  Y.,  under  the  Department  supervision. 


103 


TRANSPORTATION   TUBES. 

YSTEMS  of  underground  transportation  of  mail  matter  and  packages  are  in  general  use  in 
London,  Vienna,  Paris  and  Berlin.  The  motive  power  employed  is  compressed  air  or  a 
vacuum.  In  New  York  City,  the  Western  Union  Telegraph  Company  operates  an 
underground  system  for  the  transmission  of  telegrams.  The  central  office,  at  Broadway 
and  Dey  Street,  is  connected  with  the  main  branch  office  at  Fifth  Avenue  and  23d  Street  by  four 
tubes — two  express,  two  local.  These  tubes  run  under  Broadway  to  I4th  Street,  thence  to  Fifth 
Avenue,  and  under  that  thoroughfare  to  23d  Street.  The  distance  is  just  three  miles,  and  the  time 
consumed  by  a  carrier  in  transit  is  seven  minutes.  All  the  principal  newspaper  offices  are 
connected  by  a  single  tube,  the  right  of  way  being  governed  by  touching  a  button.  The  newspaper 
and  exchange  tubes  are  operated  by  compressed  air,  but  vacuum  is  used  upon  the  main  line.  The 
diameter  of  the  tubes  is  three  inches.  The  Philadelphia  Post  Office  operates  a  short,  under- 
ground tube  system  to  a  branch  office.  Compressed  air  is  the  power  employed.  Several  systems  of 
underground  transit  have  been  advocated  from  time  to  time,  among  them  being  a  method  of 
propelling  balls  through  a  tube  by  applying  a  vacuum  in  front  and  compressed  air  behind. 

That  system  which  will  come  at  length  into  general  use,  must  possess  great  simplicity, 
as  repairs  upon  an  underground  system  are  both  tedious  and  expensive. 


104 


AERATED  FUEL. 

HE  formation  oi  a 
highly  combustible 
spray  composed  of 
petroleum  and  com- 
pressed air,  has  been  found  to 
offer  a  most  effective,  convenient 
and  inexpensive  fuel.  By  means 
of  an  air  regulator  the  compressor 
maintains  a  uniform  pressure  of 
from  10  to  20  pounds  to  the 
square  inch,  as  the  case  demands. 
The  pressure  upon  the  oil  forces 
it  out  of  the  burners  in  a  fine 
spray,  which,  upon  being  ignited, 
becomes  a  steady  and  powerful 
flame.  Wherever  it  is  possible 
the  burners  are  arranged  opposite 
each  other  so  that  on  being 
lighted  the  flames  mingle,  an 
adjustment  which  not  only 


makes  the  sheet  of  flame  TilK0'        continuous,  but  serves  also  to 

burn  every  particle  of  oil,  some  of  which  otherwise,  by 

pressure  or  too  rapid  expulsion,  -  might  fall  to  the  ground.  Combustion 
by  this  method  is  so  complete  that  no  receptacles  and  drip  pans  are  required.  The  oil  and  air  valves 
control  the  amount  of  flame  at  all  times,  and  the  burners  may  be  placed  in  any  position.  From 
the  accompanying  illustrations  the  mechanism  will  be  understood  readily.  In  each  burner  cylinder 
there  is  a  float  which  keeps  the  oil  at  the  proper  height  by  automatically  opening  and  closing 
a  valve,  thus  preventing  the  oil  from  rising  above  the  mean  level  established  at  any  one  factory. 

The  advantages  of  the  system  are  said  to  be  an  absolutely  even  fire,  at  all  times  under 
instant  control,  thus  yielding  any  degree  of  heat  desired,  and  economy  in  labor  and  fuel.     Aerated 

1 06 


petroleum  fuel  is  especially  adapted  to  all  kinds  of  iron  and  steel  forging,  tempering,  welding  and 
annealing  ;  making  tin  plate  ;  glass  works  ;  furnaces  ;  burning  lime,  brick,  etc. ;  heating  chemicals 
and  asphalt ;  japanning  and  oxidizing.  An  effective  system  of  garbage  burning  by  this  method  has 
also  been  devised.  The  furnace  or  receptacle  for  the  garbage  is  placed  below  the  level  of  the 
ground,  or  the  floor  of  the  building  used  for  this  purpose.  In  this  floor  are  arranged  movable  caps 
covering  the  dump  holes  for  the  garbage,  the  garbage  being  dumped  into  the  furnace  below. 
There  are  placed  at  regular  intervals  on  each  side  of  the  outside  wall  of  the  furnace  a  number  of  the 
burners  used  in  this  system,  the  number  depending,  of  course,  upon  the  size  of  the  furnace.  The 
gases  which  arise  from  the  garbage  are  also  met  by  burners  and  destroyed  by  the  intense  heat. 


107 


AERATING  WATER. 

ITH  the  rapid  increase  of  population  in  towns  and  cities,  the  purity  of  the  water 
supply  has  become  more  and  more  difficult  to  maintain,  while  scientific  research 
has  annually  increased  the  evidence  that  the  quality  of  water  is  the  most  important 
factor  in  the  health  of  the  community.  It  has  thus  become  necessary  for  cities  so 
located  that  their  water  supply  is  impure,  or  subject  in  transit  to  contamination,  to  erect  filter 
stations  where  the  entire  supply  of  water  as  it  passes  to  the  mains  may  be  subjected  to  a  rigid 
filtering  process.  Careful  experiment,  however,  has  demonstrated  that  filtration  is  frequently  only 
part  of  the  process  required  to  supply  the  community  with  wholesome  water. 

Pond  water,  or  water  drawn  from  sluggish  sources,  may  contain  organisms  which  are 
offensive  to  taste  and  smell,  and  which  can  be  expelled  only  by  thorough  aeration.  The  air 
compressor  thus  has  been  found  a  most  valuable  adjunct  to  the  principal  systems  of  filtration.  The 
filter  illustrated,  consists  of  a  cylindrical  steel  shell  built  to  withstand  any  desired  pressure.  The 
water  is  introduced  along  a  conduit  running  the  entire  length  of  the  filter  just  beneath  the  crown. 
It  filters  through  4  feet  of  coke  and  sand  and  passes  out  by  cone  valves.  These  valves  are  imbedded 
permanently  in  the  cement  floor  and  flush  with  it.  They  are  filled  with  screened  quartz  gravel. 
Most  impurities  in  the  water  can  thus  be  caught,  but  peaty  matter  and  certain  other  impurities,  as 
well  as  some  kinds  of  bacteria,  require  the  addition  to  the  water  of  a  coagulant  or  precipitant 
previous  to  filtration.  The  filters  used  by  various  cities  in  connection  with  their  water  works  vary 
in  capacity  from  100,000  gallons  per  24  hours  to  5,000,000,  and,  as  an  evidence  of  value,  it  is 
estfmated  that  the  filters  at  Little  Rock,  Ark.,  remove  over  half  a  ton  of  solid  dirt  and  filth  from 
every  million  gallons  of  water  filtered. 

1 08 


The  cleansing  of  the  filters  is  accomplished  by  flooding  them  in  reverse;  the  adjustments 
being  such  that  the  entire  force  of  the  flood  is  applied  to  one-third  of  the  filter  at  a  time.  The  cleansing 
process  occupies  but  a  quarter  of  an  hour,  and  is  applied  to  each  filter  in  the  plant  separately,  so  that 
while  one  is  being  cleaned  the  others  are  at  work.  After  filtration  the  water  is  aerated.  The  air, 
sweeping  through  the  water  under  pressure,  scrubs  and  cleanses  it,  carrying  away  the  gases  and 
volatile  matter,  which  may  have  made  it  offensive  to  taste  and  smell.  In  highly  colored  water,  the 
dissolved  oxygen  is  only  one-seventh  of  the  requirement,  and  in  other  water  from  one-third  to  one- 
quarter.  The  air  compressor  supplies  this  much  needed  deficiency  by  forcing  air  through  the  water 
in  every  direction  ;  completes  the  filtration  and  renders  the  water  fresh,  sweet  and  sparkling. 


REFINING  ASPHALT  BY  COflPRESSED  AIR. 

HE  asphalt  pavements  which  are  so  largely  used  in  Paris,  and  many  American  cities,  are 
composed  of  refined  asphalt,  often  called  bitumen,  with  oil  and  sand  added  in  moderate 
quantities.  Much  of  the  asphalt  used  in  the  United  States  is  obtained  from  the  Island 
of  Trinidad,  a  British  possession  lying  about  ten  miles  off  the  coast  of  Venezuela.  The 
asphalt  occurs  as  a  natural  phenomenon.  It  is  found  floating  on  the  surface  of  a  fresh  water  lake, 
about  So  feet  above  the  sea,  and  probably  owes  its  origin  to  vegetable  matter  subjected  to  a  slow 
process  of  decay,  resulting  in  the  production  of  bituminous  coal,  from  which  by  some  action, 
volcanic  or  otherwise,  the  asphalt  has  been  distilled  and  diffused  as  a  pitchy  substance. 

In  its  natural  state  asphalt  is  not  homogeneous,  and  it  is  too  soft  for  satisfactory  results. 
The  crude  asphalt  is  therefore  placed  in  large  kettles  through  which  pass  hot  air  or  steam  tubes,  and 
for  three  or  four  days  it  is  kept  at  the  boiling  point,  during  which  period  agitation  is  an  absolutely 
necessary  requirement.  For  this  purpose  compressed  air  is  used.  Pipes  pierced  with  small  holes  are 
so  arranged  in  the  kettle  that  the  largest  distribution  of  air  can  be  obtained,  and  through  these  holes 
air  at  moderate  pressure  is  forced.  During  the  early  part  of  the  process  the  air  reaches  the  surface 
of  the  thick,  black  mass  of  asphalt,  in  the  form  of  huge  bubbles,  but  as  the  boiling  progresses,  the 
asphalt  becomes  thinner,  and  seethes  and  boils  under  the  pressure  of  the  air  forced  everywhere 
through  the  kettle.  On  being  taken  from  the  kettles,  after  cooling,  the  asphalt  appears  as  a  hard, 
black,  brittle  substance.  It  is  barrelled,  and  is  then  ready  for  use.  No  other  satisfactory  method 
of  stirring  asphalt  while  boiling  has  been  devised.  The  refining  process  must  be  at  once  thorough  and 
inexpensive,  and  compressed  air  so  perfectly  fills  these  requirements  that  it  has  become  an  indispensable 
factor.  A  system  somewhat  resembling  this  is  employed  for  agitating  syrups  in  sugar  refineries. 


INCREASING  THE  BRILLIANCY  OF  LAHPS  BY  COMPRESSED  AIR. 

)  I  (HERE  are  several  methods  of  applying  compressed  air  to  oil,  in  order  to  increase  the  surface 

JL       and  brilliancy  of  the  flame.     One  method,  known  as  the  Lucigen,   atomizes  the  oil  for 

illumination.     Air  compressed  to  a  pressure  of  from  10  to  30  pounds,  according  to  the 

characteristics  of  the  oil  used,  forces  the  oil  through  a  nozzle  where  oil  and  air  mingled  form  a 

spray,   which  upon  being  ignited,  yields  a  large,  clear  flame  of  great  illuminating  power,  and 

capable  of  successful  employment  even  in  rain  and  high  wind. 

About  one  gallon  of  oil  per  hour  and  60  cubic  feet  of  free  air  under  pressure  are  required 
to  maintain  a  flame  5x30  inches.  The  illuminating  power  of  this  flame  is  reckoned  at  1,000 
candles.  Lamps  of  this  character  are  of  much  service  where  diffused  light  of  great  power  and  small 
expense,  is  required,  and  they  are  widely  used  in  steel  works,  machine  and  railroad  shops,  and  for 
open  air  service. 

112 


MIXING  NITRO-GLYCERINE  BY  COMPRESSED  AIR. 

THE  complete  mixture  of  the  acids,  which,  with  glycerine,  form  this  high  explosive,  is  most 
thoroughly  accomplished  by  compressed  air.  By  this  method  the  process  is  accelerated, 
as  the  air  in  expanding  absorbes  heat.  The  original  process  of  delivering  the  glycerine  in  a 
spray  has  been  modified,  and  the  acid  mixture  is  now  made  in  a  lead  vat,  and  permitted  to  stand 
twelve  hours  to  cool.  600  pounds  of  nitric  acid  and  1,100  pounds  of  sulphuric  acid  are  used  ;  when 
cooled,  the  acid  mixture  is  transferred  to  the  nitro-gylcerine  apparatus,  the  water  circulating  in  it 
through  six  large  lead  worms  and  in  a  water  jacket  around  it.  The  glycerine  is  then  forced,  into 
the  acid  mixture  by  a  specially  constructed  injector  operated  by  compressed  air.  240  pounds  of 
glycerine  are  required  for  the  amount  of  acid  above  mentioned,  and  the  operation  consumes  an 
hour  and  a  half.  The  thermometer  is  constantly  watched  during  the  process,  and  if  it 
begins  to  rise,  the  operation  is  becoming  dangerous.  In  that  case  it  may  be  necessary  to  lead  off 
the  compound  to  a  tank  of  water  which  should  be  in  constant  readiness,  which  will  prevent  any 
further  danger.  After  the  addition  of  the  glycerine  is  complete,  the  mixture  is  led  into  a  lead 
separator,  where  the  nitro-glycerine  appears  at  the  surface,  and  is  skimmed  off  in  dippers,  after 
which  it  is  washed  in  water  in  a  solution  of  carbonate  of  soda. 


"3 


PAINTING  BY  COMPRESSED  AIR. 

EPEATED  experiments  in  atomizing  paint  by  compressed  air,  have  resulted  in  successfully 
applying  pigments  to  great  surfaces;  as  well  as  perfecting  the  air  brush,  by  which  a 
marvellously  delicate  application  of  color  to  portraits  and  pictures,  can  be  secured.  These 
are  the  extremes  of  practically  the  same  idea.  It  is  needless  to  refer  to  the  demand  for  some 
rapid  method  of  painting  large  surfaces,  to  replace  the  expensive  and  laborious  system  of  scaffolding 
and  paint  brush.  The  idea  of  atomizing  paint  and  projecting  it  as  a  spray  against  a  wall  or  surface, 
by  using  compressed  air,  is  not  new,  but  a  practical  difficulty  has  been  presented  by  the  thickness 
and  weight  of  the  paint,  and  the  impossibility  of  finding  hose  that  would  withstand  the  action  of 
the  pigment.  It  has  been  found  that  by  reducing  the  paint  and  heating  it,  these  difficulties  may 
be  largely  overcome,  and  though  this  device  is  still  experimental,  the  Mines  Building  at  the 
Columbian  Exposition  was  painted  in  this  way.  Experiments  in  atomizing  paint  have  recently  been 
made  by  one  of  the  large  producers  of  corrugated  iron,  for  the  purpose  of  reducing  the  time  and 
labor  necessary  to  paint  the  great  number  of  iron  sheets  used  in  the  construction  of  iron  buildings. 
The  sheets  are  placed  upright  in  a  trough  and  the  paint  is  led  through  hose  to  a  nozzle,  where  it  is 
met  by  moderate  air  pressure  and  forced  out  in  the  form  of  spray.  By  this  device  large  surfaces 
can  be  successfully  and  quickly  painted,  the  aeration  imparting  an  especially  high  gloss. 

The  air  brush  has  been  perfected  and  is  now  in  general  use.  It  consists  of  a  pencil  six 
inches  in  length  and  half  an  inch  in  diameter,  terminating  in  a  pointed  cap.  The  upper  part  of  the 
brush  is  a  reservoir  for  paint,  a  screw  on  the  upper  end  regulating  its  flow  into  the  receptacle.  In  the 
lower  part  of  the  brush  there  is  a  connection  and  valve  for  the  compressed  air,  which  is  generated  by  a 


little  compressor  operated  by  the  foot.  Above  this  valve  there  is  a  button  admitting  air  as  desired, 
which,  passing  under  the  paint  in  the  receptacle,  is  expelled  at  the  point  of  the  cap,  carrying  paint 
with  it  as  a  fine  spray.  The  amount  of  paint  actually  atomized  is  regulated  by  a  rod,  which  runs 
through  the  receptacle  (see  cut),  and  the  point  of  which  fits  into  the  cap.  The  supply  of  paint 
atomized  of  course  decreases  the  more  tightly  the  rod  is  adjusted  to  the  cap.  This  adjustment  is 
made  at  will  by  a  little  thumb  screw  in  the  receptacle. 


THE   COMPRESSED    AIR    BRUSH. 


RAISING  ACIDS. 

In  the  manufacture  of  acids,  particularly  the  oil 
of  vitriol,  the  newly  formed  acid  is  permitted  to  flow 
into  an  egg-shaped  vat  situated  in  the  cellar  of  the  build- 
ing or  partly  buried  in  the  ground.  The  capacity  of 
these  vats  varies  from  400  to  500  gallons.  The  appli- 
cation of  compressed  air  to  the  surface  of  the  acid  is 
universally  employed  in  chemical  works  and  forms  the 
only  known  method  of  pumping  these  liquids,  as 
ordinary  pumps  cannot  be  applied.  The  acid  flows 
into  the  vat  through  the  acid  pipe,  as  shown  in  the 
accompanying  cut.  When  it  reaches  a  certain  height, 
the  valve  is  shut,  cutting  off  the  inflow,  and  connec- 
tion is  opened  with  receptacles  for  the  storage  of  the 
acid.  The  lid  of  the  vat  is  then  clamped  down, 
being  made  air  tight  by  rubber  adjustment,  and  the 
valve  in  the  air  pipe  is  opened,  and  compressed  air 
admitted  to  the  surface  of  the  acid  in  the  vat.  The 
pressure  thus  secured  forces  the  liquid  through  the 
open  valve  to  any  required  elevation. 

IN  LARD  REFINERIES,  this  method  is  employed  with 
great  success  for  conveying  lard  in  process  of  refinement  from  one  department  to  another. 

116 


MAKING  SILK  FROfl  WOOD  PULP. 

N  the  Consular  Reports  for  March,  1893,  Francis  B.  Loomis,  U.  S.  Consul  at  St.  Etienne, 
France,  reports  the  discovery  of  a  process  for  making  silk  from  wood  pulp.  An 
important  feature  of  this  discovery  is  the  use  of  compressed  air.  Silk  from  wood 
pulp  (sometimes  called  cellulose  silk)  is  the  invention  of  Count  de  Chardonnet. 
The  pulp  is  carefully  dried  in  an  oven  and  plunged  in  a  mixture  of  sulphuric  and  nitric  acids  ; 
then  washed  in  several  baths  of  water,  and  dried  by  alcohol.  The  product  thus  prepared  is 
dissolved  in  ether  and  pure  alcohol,  and  the  result  is  collodion  in  viscous  form. 

This  substance  is  then  enclosed  in  a  solid,  air  tight  receptacle,  furnished  with  a  filter  in 
the  lower  end.  Compressed  air  is  applied,  and  by  the  air  pressure  the  collodion  is  forced  through 
the  filter,  which  removes  all  impurities,  into  a  tube  placed  horizontally.  This  tube  is  armed  with 
300  cocks,  the  spouts  of  which  are  made  of  glass,  pierced  by  a  small  hole  of  the  diameter  of  the 
thread  of  a  cocoon  as  spun  by  a  silk  worm.  The  spinner  opens  the  cock  and  the  collodion  issues 
in  a  thread  of  extreme  delicacy  (it  takes  six  to  make  a  thread  of  the  consistency  for  weaving).  The 
glass  tube  is  surrounded  by  a  small  reservoir  of  water,  and  as  the  thread  issues  from  the  aperture 
the  water  takes  up  the  ether  and  alcohol.  This  solidifies  the  collodion  and  transforms  it  into  a 
resisting,  brilliant,  silk-like  thread. 

The  principal  defects  at  present  in  this  invention  are  said  to  be  the  inequality  of  the 
product,  inflammability,  (though  this  defect  has  been  in  part  remedied  by  a  bath  in  solution  of 
ammonia),  and  the  snapping  of  the  thread.  It  is  claimed,  however,  that  all  these  difficulties  can 
be  overcome. 

117 


HYDRAULIC  COnPRESSED  AIR  SYSTEH  OF  SEWERAGE. 


NO  system  of  sewerage  equals  natural 
gravitation,  and  artificial  methods  of  moving  and 
expelling  sewage  are  of  course  only  required  in 
cases  where  the  town  or  city  is  so  located  that 
gravitation  is  not  available,  or  too  slight  to  be 
effective.  In  such  cases,  compressed  air  becomes 
an  important  factor,  and  a  system  has  been  devised 
by  which,  at  moderate  expense,  any  town  or  city, 
regardless  of  natural  disadvantages,  can  be 
equipped  with  an  effective  and  healthful  com- 
pressed air  sewerage  system. 

At  a  central  power  plant  compressors 
generate  and  distribute  compressed  air  to  various 
stations,  each  station  being  the  outfall  of  the 
district  about  it,  and  from  each  the  sewage  is 
automatically  expelled  into  a  main  that  leads  to 
the  common  outlet. 

The  town  is  first  divided  into  districts, 
varying  according  to  population  or  formation. 


118 


At  some  convenient  point  in  the  district,  an  ejector  station  is  erected  for  all  the  sewers  in  the  district, 
which  are  so  laid  as  to  carry  all  the  sewage  to  the  station,  as  quickly  as  possible.  There  it  falls 
through  an  inlet  pipe  into  the  compressed  air  ejector.  As  the  sewage  gradually  rises  in  the  ejector, 
it  carries  upward  with  it  a  little  rod  which  at  a  certain  height  automatically  closes  the  inlet  pipe,  and 
opens  a  valve  in  the  compressed  air  reservoir.  The  air  then  flows  into  the  ejector  and  forces  the 
solid  and  liquid  contents  through  the  outlet  pipe  into  the  high  level  gravitation  pipes  or  discharge 
mains.  The  air  valve  in  the  ejector  remains  open  until  practically  all  the  sewage  has  been  expelled, 
when  by  a  reverse  automatic  arrangement,  it  is  closed  and  the  inlet  opened.  The  advantages  of 
this  system  are  the  reduction  of  working  parts  to  the  smallest  number  and  simplest  sort,  and  the 
absence  of  finished  surfaces.  It  should  also  be  noted  that  the  ejector  forms  a  cylinder  in  which  the 
air  itself  is  the  piston  and  there  is,  therefore,  no  leakage,  friction,  slip,  or  clogging  of  machinery. 

RAISING  BEER  BY  COMPRESSED  AIR.— 
The  elevation  of  beer,  ale,  porter,  etc.,  from  kegs 
in  the  cellar  is  generally  accomplished  by  com- 
pressed air,  though  the  compressor  is  usually  a 
small  hand  pump,  or,  as  shown  in  the  cut,  a 
hand  wheel  compressor.  These  are,  of  course, 
able  to  produce  but  low  pressure,  the  requirements 
in  these  cases  being  light.  Instead  of  the  hand  com- 
pressor here  shown,  one  known  as  the  Hydro  Pneu- 
matic Pump  is  largely  used.  The  air  pump  is  oper- 
ated by  the  hydrant  pressure  of  the  water.  (See  articles  upon  emptying  acid  tanks,  elevating  oil,  etc.) 


COMPRESSING  OXYGEN  AND  OTHER  GASES. 

THE  Brin  process  of  producing  oxygen  requires  no  chemicals,  but  by  using  an  air  compressor, 
oxygen  is  extracted  from  the  atmosphere.     The  process  is  :     A  retort  charged  with  absolutely 
pure  anhydrous  oxide  of  barium,  is  raised  to  a  temperature  of  1,400°  Fahrenheit.     Into  this 
retort  an  air  compressor  passes  air  which  has  been  first  purified  by  lime  and  caustic  soda. 
The  oxide  of  barium  in  the  retort  absorbs  the  oxygen,  while  permitting  the  nitrogen  to  escape, 
thus  completely  separating  the  two  gases.       When  the  barium  oxide   has  become  sufficiently 
peroxidized  the  compressor  is  reversed  by  an  automatic  arrangement,  and  the  oxygen  which  has 
been  absorbed  is  yielded  up  into  vacuum  and  conveyed  by  pipes  to  a  tank.     The  process  is  then 
repeated. 

The  uses  for  oxygen  are  rapidly  increasing  with  the  lessening  cost  of  production.  With 
hydrogen,  oxygen  is  widely  used  in  theatres  for  calcium  or  lime  lights.  It  is  used  with  hydrogen 
as  a  blow  pipe,  developing  such  enormous  heat  that  platinum  may  be  readily  melted.  It  is  also 
of  extraordinary  value  in  sustaining  life  in  cases  of  pneumonia  and  other  lung  diseases. 

Other  uses  are,  thickening  oil  (as  in  the  manufacture  of  linoleum,)  eliminating  sulphur 
from  coal  gas,  and  in  aerating  water,  the  latter  having  especially  valuable  medicinal  properties  for 
rheumatism,  diabetes  and  dyspepsia.  The  manufacture  of  oxygen  in  Europe  is  practically  controlled 
by  one  Company,  which  has  an  associate  organization  in  this  country,  the  New  York  Oxygen 
Company. 

Pure  nitrogen  may  be  obtained  by  passing  it  through  an  additional  barium  charged 
retort,  the  operation  being  similar  to  that  for  oxygen.  The  process  is  purely  mechanical,  as  the 

120 


STAGE  VERTICALS  s 

CH  PRESSURE  COMPRESSOR.^! 

V  ^ 


I 


barium  oxide  remains  unaffected,  receiving  and  giving  off  like  a  sponge.  The  cost  of  raw  material 
is  therefore  literally  nothing.  From  the  receiver,  the  gas  is  conducted  to  an  especially  constructed 
compressor,  within  which  the  oxygen  is  first  compressed  to  about  70  pounds  ;  a  second  cylinder 
then  compresses  it  to  1,000  pounds,  and  a  third  to  2,000,  at  which  pressure  it  is  drawn  off  into 
weldless  steel  cylinders  which  contain  from  10  to  100  cubic  feet.  These  cylinders  are  tested  by 
hydraulic  pressure  to  stand  4,480  pounds,  and  they  have  been  further  tested,  when  fully  charged, 
by  dropping  700  pounds  of  iron  upon  them  from  a  height  of  35  feet,  and,  though  bent,  have 
retained  their  contents  uninjured.  The  gas  can  be  drawn  off  from  a  cylinder  as  desired,  by  a  stop 
cock  and  key.  A  system  of  army  balloons,  lately  devised,  is  based  upon  the  use  of  compressed 
hydrogen.  A  large  number  of  cylinders  containing  the  gas  highly  compressed  are  transported  upon 
a  specially  constructed  wagon,  accompanying  the  balloon  corps. 

RAISING  THE  PRESSURE  OF  NATURAL  GAS.— When  gas  wells  were  first  dis- 
covered, the  natural  pressure  was  generally  so  great  that  it  was  sufficient  to  carry  the  gas 
through  pipes  of  moderate  diameter  to  a  distance,  in  some  instances,  of  twenty  miles,  but 
as  the  pressure  lessened,  it  was  found  necessary  to  put  in  air  compressors,  and  by  this  device 
natural  gas  is  now  carried  i  oo  miles  from  the  source  of  supply.  It  is  not  at  all  improbable  that  in 
the  course  of  time  it  may  be  found  economical  to  make  gas  from  the  coal  of  the  dump  piles  in 
Pennsylvania  and  force  it  through  pipes  to  the  cities  far  distant.  The  photograph  shows  a  gas 
compressor  now  working  at  the  Lima  Natural  Gas  Co.,  Lima,  Ohio. 


123 


PRESERVING  TIMBER— (Vulcanizing.) 

HE  vulcanizing  process  consists  of  taking  advantage  of  the  highly  antiseptic  change 
produced  in  the  sap  of  wood  by  heat ;  while  this  chemical  change  is  in  progress  the 
application  of  compressed  air  at  high  pressure,  prevents  the  escape  of  the  sap,  and  it  is 
solidified  within  the  timber.  Thus,  by  the  application  of  heat  and  pressure  for  a  few 
hours,  any  wood  may  be  as  perfectly  seasoned  as  if  it  had  lain  for  years  under  the  most  perfect 
conditions.  The  plant  for  vulcanizing  consists  of  steel  cylinders  about  100  feet  long  and  6  feet  in 
diameter,  capable  of  sustaining  about  200  pounds  pressure.  The  timber  to  be  vulcanized  is  run  into 
these  cylinders  on  cars.  The  cylinders  are  then  closed,  and  the  temperature  raised  to  about  300 
degrees  by  superheated  steam  and  coils.  At  the  same  time  compressed  air,  at  a  pressure  of  160 
pounds,  is  applied  through  a  pipe  entering  the  cylinder  about  midway.  The  heat  and  pressure  are 
maintained  from  eight  to  twelve  hours,  and  the  cylinders  are  then  permitted  to  cool,  still  under 
pressure.  The  advantages  of  the  process  are  many.  Decay  is  made  impossible,  by  hardening  the 
wood  and  retaining  every  preservative  quality.  The  life  of  vulcanized  timber  is  therefore  unlimited, 
making  it  of  extraordinary  value  in  outdoor  service  such  as  railroad  ties,  telegraph  poles  and  arms, 
and  ship  timber.  The  strength  and  resistance  of  wood  are  increased  1 8  per  cent,  by  this  process  ; 
cracking  and  warping  are  rendered  impossible  ;  and  color  and  brilliancy  are  so  much  improved  that 
vulcanized  wood  is  now  largely  used  in  cabinet  work  and  house  finishing.  By  this  means,  also, 
antique  oak  of  richest  tint  may  be  produced  from  green  timber.  The  process  of  vulcanizing  wood 
has  already  been  extended  to  Europe,  and  is  coming  into  general  use  at  a  time  when  the  annual 
consumption  of  timber  is  twice  the  natural  growth.  By  extending  indefinitely  the  life  of  useful 

125  i 


timber  and  making  of  value  wood  otherwise  useless,  vulcanizing  may  offer  the  ultimate  solution  of 
that  troublesome  problem  of  forest  destruction. 

RAISING  SUNKEN  VESSELS  BY  COMPRESSED  AIR.— Many  methods  have  been 
devised  from  time  to  time  to  raise  vessels,  by  employing  compressed  air,  the  essential  feature  being 
the  adjustment  of  bags  in  or  about  the  wreck,  after  which  air  was  forced  into  the  bags,  raising  the 
wreck  by  the  buoyancy  thus  imparted.  One  method,  employed  in  England  in  1 870,  was  to  place 
pontoons  about  the  wreck,  to  each  of  which  was  attached  a  small  cylinder  of  compressed  air.  By  a 
valve  the  air  was  permitted  to  expand  into  the  pontoon,  thus  expelling  the  water,  and  the  vessel  rose. 


126 


ICE  MAKING  AND  REFRIGERATING. 

LL  refrigeration  by  mechanical  means  depends  upon  the  fact  that  heat  is  generated  by  the 
compression  of  gas  or  air,  and  that  if  this  heat  be  in  any  way  absorbed,  and  the  air  be 
then  expanded  to  its  original  pressure,  the  expansion  will  cool  it  in  the  same  way  that 
the  compression  heated  it — the  temperatures  obtained  in  this  way  being  many  degrees 
below  zero.  The  system  of  refrigeration  which  employs  air  instead  of  ammonia  and  other  gases,  has 
distinct  advantages  for  many  places,  notably  on  ship  board.  The  illustration  is  made  from  a 
photograph  of  a  machine  furnished  to  one  of  the  flag-ships  of  the  navy.  This  machine,  by  reason 
of  its  compactness,  is  specially  adapted  for  marine  use.  It  has  three  cylinders — one  for  steam, 
one  for  compressing,  and  one  for  expanding  the  air — the  cranks  being  all  on  the  same  shaft. 
The  system  comprises  the  compression  of  the  air,  the  absorption  of  the  heat  generated,  and  the 
expansion  of  the  air  in  a  cylinder  similar  to  the  steam  cylinder — the  air  in  its  expansion  thus  doing 
useful  work,  and  assisting  in  driving  the  machine.  After  expansion  the  cold  air  is  circulated  through 
the  rooms  to  be  cooled,  in  closed  pipes,  after  which  the  same  air  is  returned  to  the  machine  to  be 
used  over  and  over — this  cycle  of  operations  being  indefinitely  repeated.  Any  incidental  leakage 
of  air  is  supplied  by  a  small  auxiliary  pump. 

The  system  of  refrigerating  by  compressed  air,  is  meeting  with  great  favor  in  many 
Western  cities,  and  the  practicability  of  piping  the  streets  and  supplying  cold  air  for  business  and 
private  requirements,  has  been  actively  discussed  in  St.  Louis  and  elsewhere.  Investigation  in  St. 
Louis  showed  that  in  a  business  quarter  five  miles  in  extent,  $172,000  was  annually  expended  for 
ice  at  $4  per  ton,  a  figure  which  would  make  a  compressed  air  plant  a  profitable  investment. 

127 


THE  COMPRESSED  AIR  TIRE. 

THE  application  of  compressed  air  to  the  tires  of 
vehicles  is  said  to  be  at  least  50  years  old,  and  at  that 
time  it  was  proposed  to  make  them  with  an  inner  tube 
and  cover  of  leather.  The  practical  application  to 
bicycles,  however,  is  said  to  have  been  first  made  in 
England  in  the  form,  substantially,  of  an  endless  hose, 
which  was  cemented  to  the  rim.  In  this  form  the  tire 
was  intended  to  be  thick  enough  to  withstand  the  cuts 
of  sharp  stones,  but  even  though  so  made,  punctures 
occurred,  necessitating  the  return  of  the  tire  to  the  manu- 
facturer, which  led  to  the  design  of  a  detachable  cover 
and  inner  tube.  This  is  the  tire  now  in  most  general 
use.  It  is  said  to  be  a  French  invention.  The  inner  tube 
is  made  of  pure  gum  elastic  rubber  about  i  -32  of  an  inch 
thick.  The  tube  when  inflated  is  about  i  3-8  inches  in 
diameter.  A  patch  holding  the  projecting  valve  is  put  on 
one  side  of  the  tube  before  vulcanization.  The  strip  of 
tubing  is  cut  in  suitable  lengths  to  form  the  circle  ;  one 
end  is  then  inserted  in  the  other,  and  they  are  cemented 
together.  The  outer  cover  is  formed  of  layers  of  canvas 

129 


SECTION    OF    BICYCLE    TIRE. 


and  rubber — thicker  on  the  tread  por- 
tion, and  about  i  $£  inches  in  diameter. 
The  method  of  application  of  the  tire 
shown  in  the  cut  on  the  opposite  page 
is  to  lace  protecting  flaps  over  the  inner 
tube,  through  slits.  The  cut  on  the 
this  page  illustrates  the  most  recent 
device.  This  method  is  to  fasten  one 
side,  then  place  the  inner  tube  in  its 
place,  bring  the  cover  down  over  it  and 
fasten  the  latter  to  the  rim  by  means  of 
the  binding  wire. 

The  speed  made  by  experts  upon 
the  bicycle  in  races,  is  said  to  have  in- 
creased within  a  few  years'  time,  about 
1 8  per  cent,  according  to  the  testimony 
of  experts,  and  much  of  this  is  due  to 
improved  machines  and  the  better  skill 
and  endurance  of  man.  But  after  these 
factors  have  been  deducted  the  same 
experts  express  the  opinion  that  10  per 
cent,  of  the  increase  is  due  to  the  pneu- 


matic  tire.  The  same  experts  say  that  while  the  races  upon  the  solid  wheels  produced  stagnation  of 
blood  in  the  lower  limbs,  the  pneumatic  tire  prevents  any  such  effect.  There  is  a  notable  differ- 
ence in  the  increase  of  speed  obtained  by  the  pneumatic  tire  applied  to  a  bicycle  and  to  a  sulky,  as 

the  estimate  is  made  that  the  advantage  in 
the  latter  case  is  about  three  per  cent. 

Experts  differ  greatly  as  to  what  may  be 
called  the  life  of  a  bicycle  tire,  but  it  would 
seem  to  be  a  safe  statement  to  make,  that 
when  the  tires  are  used  by  professionals,  on  the 
road  as  well  as  in  the  ring,  three  or  four  are 
required  during  the  season.  Perhaps  the  aver- 
i  age  life  of  a  compressed  air  tire  may  be  stated 
I  as  about  one  year. 

The  pneumatic  tire  has  not  come  into 
such  general  use  for  road  wagons  and  carri- 
ages, but  is  used  very  generally  on  sulkies. 
The  wagon-wheel  tire  is  substantially  the 
same  as  that  already  described.  The  illustra- 
tion shows  a  popular  pneumatic  tire  for  road 
wagons.  The  triple  tube  shows  the  sections  of 
the  tire.  The  smallest  section  is  the  air  tube, 
AIR  TIRE  ON  A  ROAD  WAGON.  made  of  specially  prepared  stock,  the  air  valve 


151 


SECTION    OF    A    TIRE    ON    A    ROAD    WAGON. 


being  vulcanized  to  the  air  tube.  The  second 
section  shows  the  restraining  jacket  en- 
veloping the  air  tube,  and  made  of  Sea 
Island  cotton  of  peculiar  construction  to 
avoid  stretching.  Outside  of  this  is  the 
wearing  shoe,  which,  like  the  inner  tube,  i' 
^  of  finest  material,  but  is  not  subjected  to  any 
air  pressure.  It  is  thus  apparent  that  each 
section  performs  special  service,  and  it  is  said 
they  together  form  a  most  satisfactory  and 
durable  tire,  effectually  deadening  cobblestone 
pavements  and  rough  roads. 

The  principle  of  the  pneumatic  tire,  has 
been  applied  even  to  roller  skates.  A  Scotch 
manufacturer  makes  a  skate  that  meets  all  the 
requirements  of  road  travelling,and  which  straps 
or  clamps  to  the  shoe  like  the  ordinary  skate. 
The  rollers  are  3^  inches  in  diameter,  the  tires 
2  inches,  and  the  average  weight  of  each  skate 
2  ^  pounds.  The  rollers  are  fitted  with  ball 
bearings,  and  run  noiselessly. 


132 


TRANSfllSSION  OF  POWER. 

SCIENTIFIC  experiment  has  discovered  but  four  methods  of  transmitting  power — steam, 
water,  compressed  air  and  electricity:  and  of  these,  steam  and  water  are  open  to  serious 
objections.      The  use  of  compressed  air  distributed  through  the  streets  in  Paris  and  Birming- 
ham, England,  has  developed  numerous  uses  not  originally  contemplated.     New  works,  located 
near  the  river  Seine  for  convenience  of  supplies  of  coal  and  water,  have  recently  been  erected, 
and  the  design  contemplates  an  aggregated  power  equal  to  25,000  horses.     A  major  part  of  the 
power  is  now  issued  to  operate  engines  running  dynamos  for  electric  lighting  purposes  scattered 
throughout  the  city.     The  exhaust  from  the  engines  is  used  for  refrigerating  purposes,  and  for 
ventilation  when  the  engine  is  located  in  or  near  a  hotel,  restaurant,  or  theatre. 

This  also  serves  to  keep  the  temperature  above  the  freezing  point  after  exhaust.  An  English 
engineer  declares  that  a  quarter  of  a  pound  of  coke  per  hour  per  indicated  horse  power  is  sufficient 
to  heat  the  air  required  in  a  moderate  sized  expansion  engine,  and  5  pounds  of  coke  per  hour 
sufficed  for  an  engine  indicating  20  horse  power,  enabling  it  to  maintain  the  whole  system  at  80 
per  cent  of  proficiency. 


133 


Other  uses  of  compressed  air  are — for  refining  silk  ribbon,  for  removing  the  hose  from 
iron  mandrels  in  rubber  hose  factories,  operating  sand  blasts,  automatic  fire  extinguishers,  increasing 
the  pressure  on  hydraulic  elevator  tanks,  and  for  indicators  and  bells  in  elevators,  houses  and  shops. 


134 


INDEX. 


Acids,  Raising,    -        -        -        -        -  1 1 6 

Aerated  Fuel,             -        -.      -        -  105 

Aerated  Water,    -         -        -        -        -  108 

Air  Brake,         -----  43 

Air,  Compared  with  Hydraulic  Power.  75 
Air  Compressor,  Construction  of.     (See 

Compressor.)  9 

Air  Lift  Pump  37 

Angle  Iron  Shears.     (See  Shears.)           -  61 

Asphalt,  Refining,     -        -        -        -  1 1 1 

Automatic  Fire  Extinguishers,        -  1 34 

Automatic  Pump,     -  42 

Automatic  Railroad  Safety  Appliances,  -  49 

Balloons,  Army  System  of,        -        -  1 23 

Beef,  Lifting,        -        -    -    -        -        -  53 

Beer,  Raising,            -        -         -         113,  119 
Belleville,    (Paris),  France,   Compressed 

Air  Power  Station  in,  86 


Berne,  Switzerland,  Street  Railroads  in,  70 

Blow  Pipe,  Increasing  heat  at,       -        -  71 

Brake,  Compressed  Air.    (See  Air  Brake.)  43 

Caissons,  Working  and  Drilling  in,         -  23 

Car  Cushions,  Cleaning,    -        -        -  63 

Carpets,  Cleaning,         -        -         -        -  63 

Cars,  Unloading,      -  68 

Clocks,  Operating,  in  Paris,  -        -  86 

Coal  Mining  Machines,      -  88 

Copying  Letters,       -  65 
Cranes,   Walking   Shop   and   Overhead 

Travelling,    -----  80 


Destroyer,  Operating  Gun  on, 
Drilling.     (See  Rock  Drills.) 


'7 


Electricity,    Generated    by   Compressed 

Air, 87 


Elevators,    Increasing   Pressure  on   Hy- 
draulic,        134 

Engines,  Operated,      -        -        -      25,  133 

Filtration  by.     (See  Aerated  Water.)  108 

Fluids,  Automatic  Movement  of,   - 

Acids, 116 

Beer, 119 

Oil,  61 

Water,          -----  42 

Sewage,    -        -        -        -        -  1 1 8 

Gas,  Compressed  for  Cars,    -         -         -  63 

Gases,  Methods  of  Compressing,        -  1 20 

Gates,  Railway, 56 

Harlem  River  Bridge,  23 

Heat,  Increasing,       -        -        -        -  61 

Hoists,  Capacity  of      -        -        -        -  59 

Hoists,  for  Rails,       ....  69 

Hoists,  Overhead,        ....  80 


PAGE. 

Hoists,  Under  Floor,         ...  60 

Hydrogen,  Compression  of  -        -        -  120 

Hydrogen,  Military  Uses  of,       -        -  123 

Ice,  Making,        -        -        -        -        -  127 

Jacks,  Compressed  Air,  60 

Lamps,  Increasing  Brilliancy,         -        -  112 

Little  Rock,  Ark.,  Filtration  Plant  at,  108 

Locks,  Compressed  Air,     -        -        -  34 

Locomotive,  Compressed  Air,        -  66 

Mandrels,    Removing  in   Rubber   Hose 

Factory,  -  -  -  -  134 
Mekarksi  System  Street  Railways,  -  70 
Mining  Coal.  (See  Coal  Mining  Ma- 
chines), -  88 
Mining,  Effects  of  Drill  on,  -  -  19 
Miscellaneous  Uses  of,  -  -  -  65,  134 


Nantes,  France,  Street  Railways  in,       -  70 

Natural  Gas,  Raising  Pressure  of,       -  123 
Niagara  Falls  Power  Co.,      -        -        -12 

Niagara,  Utilizing  Power  of,               -  12 

Niagara,  Water  Power  of,     -        -        -  12 

Nitrogen,  Generation  and  Compression  of,  1 20 

Nitro-glycerine,  Mixing,        -        -        -  113 

Nogent,  France,  Street  Railways  in,  -  70 

Oil,  Forcing  from  Barrels,     -        -  6 1 

Oxygen,  Generation  and  Compression  of,  1 20 

Painting,     -        -        -        -        -        -  114 

Paris,  France,  Compressed  Air  System  in,  70 

Clock  System  in,  -        -        -        -  86 

Meters  Used  in,  86 

Street  Cars  in,                -        -  70 

Power,  Transmission  of,    -         -         -  133 

Pump,  Air  Lift,   -----  37 

Plant  at  Wayne,  Pa.,         -        -  39 

Plant  at  Rockford,  111.,           -  39 


Pump,  Driven  by  Compressed  Air,     -  42 

Punch,  Compressed  Air,  59 

Rails,  Lifting, 69 

Rails,  Sanding  for  Locomotives.     (See 

Sanding  Rails),      -        -  63 
Railway   Appliances.     (See   Air  Brake, 

ctaL), 43 

Railway  Shops,  Uses  in,                -  -      59 

Refrigerating,  -        -        -        -        -  127 

Riveter,  Portable,        -        -  78 

Rock  Drills,  Description  and  Use  of,  -  17 

Use  in  Caissons,    -         -         -  -       23 

Use  in  Tunnels,         -        -        -  17 

Tapping  Iron  Furnaces,          -  3 1 

Sanding  Rails,  63 

Safety  Appliances  for  Railroads,    -  -      49 

Sand  Blasts,   -  134 

Sewerage,  Compressed  Air  System  of,  1 1 8 


PAGE. 

Shears,  Angle  Iron,      -        ... 

61 

Shops,  Use  in,          - 

74 

Shops,  Railway,  Use  in, 

59 

Siege  of  Paris,  Food  Preservation  by  Air, 

8? 

Silk  from  Wood  Pulp,       - 

"7 

Silk  Ribbon,  Refining, 

117 

Skates,  Air  Tires,      -.-,'-- 

132 

South  Africa,  Use  of  Drills  in  Gold  Mines  of, 

'7 

Stay  Bolt  Cutter,      -        -   -  .  - 

76 

Steam  Passages,  Cleaning,    - 

61 

Street  Railways  Operated, 

70 

Syrups,  Agitating  in  Sugar  Refineries,    - 

1  1  1 

Switches,  Automatic  Railroad,  - 

49 

Timber  Preserved,        - 

125 

Tires,  Air,  for  Bicycles,      - 

129 

Tires,  Air,  for  Wagons,         - 

•3' 

Tool,  Calking, 

83 

Detail  of,      

85 

Granite  Cutting,         - 

84 

PAGE. 

Tools,  Compressed  Air,  83 

Tools  Operated,       -  74 

Torpedo  Boats.     (See  Destroyer),         -  98 

Torpedo  Gun  Operated,    -  94 

Torpedo  Gun,  on  the  Destroyer,  -  98 

Torpedo,  Locomotive,       -        -        -  102 

Tubes,  Transportation,         -         -        -  104 

Tunnelling,  Niagara,  12 

Soft  Ground,        -  34 

Trinadad,  Occurrence  of  Asphalt  in,  -  1 1 1 

Vesuvius,  U.  S.  Cruiser,  Compressed  Air 

Guns  on,      -        -        -        -  91 

Vulcanizing.     (See  Timber),      -        -  125 

Whitehead  Torpedo,    -        -        -        -  102 

Wood  Pulp,  Making  Silk  from,          -  117 

Wrecks,  Raising.          -        -        -        -  126 

Zalinski  Torpedo  Gun.     (See  Torpedo 

Gun,  and  Vesuvius),          -        -  91 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


MAR 

8    1940 

iS<yo-;  ,:^  - 

YB  52027 


